diff --git a/docs/openapi-ts/plugins/zod.md b/docs/openapi-ts/plugins/zod.md
index df445e65dd..ad6db1ae22 100644
--- a/docs/openapi-ts/plugins/zod.md
+++ b/docs/openapi-ts/plugins/zod.md
@@ -236,6 +236,34 @@ export default {
 
 :::
 
+## Nullish
+
+By default, non-required object properties generate `.optional()`, which accepts `undefined` values. If you'd like non-required properties to also accept `null`, you can set `useNullish` to `true`. This generates `.nullish()` instead of `.optional()`.
+
+::: code-group
+
+```ts [example]
+const zFoo = z.object({
+  bar: z.nullish(z.string()),
+});
+```
+
+```js [config]
+export default {
+  input: 'hey-api/backend', // sign up at app.heyapi.dev
+  output: 'src/client',
+  plugins: [
+    // ...other plugins
+    {
+      name: 'zod',
+      useNullish: true, // [!code ++]
+    },
+  ],
+};
+```
+
+:::
+
 ## Metadata
 
 It's often useful to associate a schema with some additional [metadata](https://zod.dev/metadata) for documentation, code generation, AI structured outputs, form validation, and other purposes. If this is your use case, you can set `metadata` to `true` to generate additional metadata about schemas.
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/mini/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/mini/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..f9cff5d06e
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/mini/validators-nullish/zod.gen.ts
@@ -0,0 +1,23 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4-mini';
+
+export const zBaz = z._default(z.readonly(z.string().check(z.regex(/foo\nbar/))), 'baz');
+
+export const zFoo = z._default(z.union([
+    z.object({
+        foo: z.nullish(z.string().check(z.regex(/^\d{3}-\d{2}-\d{4}$/))),
+        get bar() {
+            return z.nullish(z.lazy((): any => zBar));
+        },
+        get baz() {
+            return z.nullish(z.array(z.lazy((): any => zFoo)));
+        },
+        qux: z._default(z.nullish(z.int().check(z.gt(0))), 0)
+    }),
+    z.null()
+]), null);
+
+export const zBar = z.object({
+    foo: z.nullish(zFoo)
+});
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v3/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v3/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..e7f6a981af
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v3/validators-nullish/zod.gen.ts
@@ -0,0 +1,19 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod';
+
+export const zBaz = z.string().regex(/foo\nbar/).readonly().default('baz');
+
+export const zFoo: z.ZodTypeAny = z.union([
+    z.object({
+        foo: z.string().regex(/^\d{3}-\d{2}-\d{4}$/).nullish(),
+        bar: z.lazy(() => zBar).nullish(),
+        baz: z.array(z.lazy(() => zFoo)).nullish(),
+        qux: z.number().int().gt(0).nullish().default(0)
+    }),
+    z.null()
+]).default(null);
+
+export const zBar = z.object({
+    foo: zFoo.nullish()
+});
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v4/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v4/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..ea0ddcda3c
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.0.x/v4/validators-nullish/zod.gen.ts
@@ -0,0 +1,23 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod/v4';
+
+export const zBaz = z.string().regex(/foo\nbar/).readonly().default('baz');
+
+export const zFoo = z.union([
+    z.object({
+        foo: z.nullish(z.string().regex(/^\d{3}-\d{2}-\d{4}$/)),
+        get bar() {
+            return z.nullish(z.lazy((): any => zBar));
+        },
+        get baz() {
+            return z.nullish(z.array(z.lazy((): any => zFoo)));
+        },
+        qux: z.nullish(z.int().gt(0)).default(0)
+    }),
+    z.null()
+]).default(null);
+
+export const zBar = z.object({
+    foo: z.nullish(zFoo)
+});
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/mini/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/mini/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..13144aff2c
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/mini/validators-nullish/zod.gen.ts
@@ -0,0 +1,64 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/v4-mini';
+
+export const zBaz = z._default(z.readonly(z.string().check(z.regex(/foo\nbar/))), 'baz');
+
+export const zQux = z.record(z.string(), z.object({
+    qux: z.nullish(z.string())
+}));
+
+/**
+ * This is Foo schema.
+ */
+export const zFoo = z._default(z.union([
+    z.object({
+        foo: z.nullish(z.string().check(z.regex(/^\d{3}-\d{2}-\d{4}$/))),
+        get bar() {
+            return z.nullish(z.lazy((): any => zBar));
+        },
+        get baz() {
+            return z.nullish(z.array(z.lazy((): any => zFoo)));
+        },
+        qux: z._default(z.nullish(z.int().check(z.gt(0))), 0)
+    }),
+    z.null()
+]), null);
+
+/**
+ * This is Bar schema.
+ */
+export const zBar = z.object({
+    foo: z.nullish(zFoo)
+});
+
+/**
+ * This is Foo parameter.
+ */
+export const zFoo2 = z.string();
+
+export const zFoo3 = z.object({
+    foo: z.nullish(zBar)
+});
+
+export const zPatchFooData = z.object({
+    body: z.object({
+        foo: z.nullish(z.string())
+    }),
+    path: z.nullish(z.never()),
+    query: z.nullish(z.object({
+        foo: z.nullish(z.string()),
+        bar: z.nullish(zBar),
+        baz: z.nullish(z.object({
+            baz: z.nullish(z.string())
+        })),
+        qux: z.nullish(z.iso.date()),
+        quux: z.nullish(z.iso.datetime())
+    }))
+});
+
+export const zPostFooData = z.object({
+    body: zFoo3,
+    path: z.nullish(z.never()),
+    query: z.nullish(z.never())
+});
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v3/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v3/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..8669a24cea
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v3/validators-nullish/zod.gen.ts
@@ -0,0 +1,60 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod';
+
+export const zBaz = z.string().regex(/foo\nbar/).readonly().default('baz');
+
+export const zQux = z.record(z.object({
+    qux: z.string().nullish()
+}));
+
+/**
+ * This is Foo schema.
+ */
+export const zFoo: z.ZodTypeAny = z.union([
+    z.object({
+        foo: z.string().regex(/^\d{3}-\d{2}-\d{4}$/).nullish(),
+        bar: z.lazy(() => zBar).nullish(),
+        baz: z.array(z.lazy(() => zFoo)).nullish(),
+        qux: z.number().int().gt(0).nullish().default(0)
+    }),
+    z.null()
+]).default(null);
+
+/**
+ * This is Bar schema.
+ */
+export const zBar = z.object({
+    foo: zFoo.nullish()
+});
+
+/**
+ * This is Foo parameter.
+ */
+export const zFoo2 = z.string();
+
+export const zFoo3 = z.object({
+    foo: zBar.nullish()
+});
+
+export const zPatchFooData = z.object({
+    body: z.object({
+        foo: z.string().nullish()
+    }),
+    path: z.never().nullish(),
+    query: z.object({
+        foo: z.string().nullish(),
+        bar: zBar.nullish(),
+        baz: z.object({
+            baz: z.string().nullish()
+        }).nullish(),
+        qux: z.string().date().nullish(),
+        quux: z.string().datetime().nullish()
+    }).nullish()
+});
+
+export const zPostFooData = z.object({
+    body: zFoo3,
+    path: z.never().nullish(),
+    query: z.never().nullish()
+});
diff --git a/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v4/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v4/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..02a9cd37d9
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v3/__snapshots__/3.1.x/v4/validators-nullish/zod.gen.ts
@@ -0,0 +1,64 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod/v4';
+
+export const zBaz = z.string().regex(/foo\nbar/).readonly().default('baz');
+
+export const zQux = z.record(z.string(), z.object({
+    qux: z.nullish(z.string())
+}));
+
+/**
+ * This is Foo schema.
+ */
+export const zFoo = z.union([
+    z.object({
+        foo: z.nullish(z.string().regex(/^\d{3}-\d{2}-\d{4}$/)),
+        get bar() {
+            return z.nullish(z.lazy((): any => zBar));
+        },
+        get baz() {
+            return z.nullish(z.array(z.lazy((): any => zFoo)));
+        },
+        qux: z.nullish(z.int().gt(0)).default(0)
+    }),
+    z.null()
+]).default(null);
+
+/**
+ * This is Bar schema.
+ */
+export const zBar = z.object({
+    foo: z.nullish(zFoo)
+});
+
+/**
+ * This is Foo parameter.
+ */
+export const zFoo2 = z.string();
+
+export const zFoo3 = z.object({
+    foo: z.nullish(zBar)
+});
+
+export const zPatchFooData = z.object({
+    body: z.object({
+        foo: z.nullish(z.string())
+    }),
+    path: z.nullish(z.never()),
+    query: z.nullish(z.object({
+        foo: z.nullish(z.string()),
+        bar: z.nullish(zBar),
+        baz: z.nullish(z.object({
+            baz: z.nullish(z.string())
+        })),
+        qux: z.nullish(z.iso.date()),
+        quux: z.nullish(z.iso.datetime())
+    }))
+});
+
+export const zPostFooData = z.object({
+    body: zFoo3,
+    path: z.nullish(z.never()),
+    query: z.nullish(z.never())
+});
diff --git a/packages/openapi-ts-tests/zod/v3/test/3.0.x.test.ts b/packages/openapi-ts-tests/zod/v3/test/3.0.x.test.ts
index b9c080a5f2..f5a122ceb7 100644
--- a/packages/openapi-ts-tests/zod/v3/test/3.0.x.test.ts
+++ b/packages/openapi-ts-tests/zod/v3/test/3.0.x.test.ts
@@ -48,6 +48,20 @@ for (const zodVersion of zodVersions) {
         }),
         description: 'generates validator schemas',
       },
+      {
+        config: createConfig({
+          input: 'validators.json',
+          output: 'validators-nullish',
+          plugins: [
+            {
+              compatibilityVersion: zodVersion.compatibilityVersion,
+              name: 'zod',
+              useNullish: true,
+            },
+          ],
+        }),
+        description: 'generates validator schemas with nullish',
+      },
     ];
 
     it.each(scenarios)('$description', async ({ config }) => {
diff --git a/packages/openapi-ts-tests/zod/v3/test/3.1.x.test.ts b/packages/openapi-ts-tests/zod/v3/test/3.1.x.test.ts
index ca5a271525..814cfa7f86 100644
--- a/packages/openapi-ts-tests/zod/v3/test/3.1.x.test.ts
+++ b/packages/openapi-ts-tests/zod/v3/test/3.1.x.test.ts
@@ -48,6 +48,20 @@ for (const zodVersion of zodVersions) {
         }),
         description: 'generates validator schemas',
       },
+      {
+        config: createConfig({
+          input: 'validators.yaml',
+          output: 'validators-nullish',
+          plugins: [
+            {
+              compatibilityVersion: zodVersion.compatibilityVersion,
+              name: 'zod',
+              useNullish: true,
+            },
+          ],
+        }),
+        description: 'generates validator schemas with nullish',
+      },
       {
         config: createConfig({
           input: 'validators.yaml',
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/mini/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/mini/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..b29f0dfba6
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/mini/validators-nullish/zod.gen.ts
@@ -0,0 +1,23 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/mini';
+
+export const zBaz = z._default(z.readonly(z.string().check(z.regex(/foo\nbar/))), 'baz');
+
+export const zFoo = z._default(z.union([
+    z.object({
+        foo: z.nullish(z.string().check(z.regex(/^\d{3}-\d{2}-\d{4}$/))),
+        get bar() {
+            return z.nullish(z.lazy((): any => zBar));
+        },
+        get baz() {
+            return z.nullish(z.array(z.lazy((): any => zFoo)));
+        },
+        qux: z._default(z.nullish(z.int().check(z.gt(0))), 0)
+    }),
+    z.null()
+]), null);
+
+export const zBar = z.object({
+    foo: z.nullish(zFoo)
+});
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v3/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v3/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..95d920f50b
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v3/validators-nullish/zod.gen.ts
@@ -0,0 +1,19 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod/v3';
+
+export const zBaz = z.string().regex(/foo\nbar/).readonly().default('baz');
+
+export const zFoo: z.ZodTypeAny = z.union([
+    z.object({
+        foo: z.string().regex(/^\d{3}-\d{2}-\d{4}$/).nullish(),
+        bar: z.lazy(() => zBar).nullish(),
+        baz: z.array(z.lazy(() => zFoo)).nullish(),
+        qux: z.number().int().gt(0).nullish().default(0)
+    }),
+    z.null()
+]).default(null);
+
+export const zBar = z.object({
+    foo: zFoo.nullish()
+});
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v4/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v4/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..535dd9c79a
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.0.x/v4/validators-nullish/zod.gen.ts
@@ -0,0 +1,23 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod';
+
+export const zBaz = z.string().regex(/foo\nbar/).readonly().default('baz');
+
+export const zFoo = z.union([
+    z.object({
+        foo: z.nullish(z.string().regex(/^\d{3}-\d{2}-\d{4}$/)),
+        get bar() {
+            return z.nullish(z.lazy((): any => zBar));
+        },
+        get baz() {
+            return z.nullish(z.array(z.lazy((): any => zFoo)));
+        },
+        qux: z.nullish(z.int().gt(0)).default(0)
+    }),
+    z.null()
+]).default(null);
+
+export const zBar = z.object({
+    foo: z.nullish(zFoo)
+});
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/mini/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/mini/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..d77facff17
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/mini/validators-nullish/zod.gen.ts
@@ -0,0 +1,64 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import * as z from 'zod/mini';
+
+export const zBaz = z._default(z.readonly(z.string().check(z.regex(/foo\nbar/))), 'baz');
+
+export const zQux = z.record(z.string(), z.object({
+    qux: z.nullish(z.string())
+}));
+
+/**
+ * This is Foo schema.
+ */
+export const zFoo = z._default(z.union([
+    z.object({
+        foo: z.nullish(z.string().check(z.regex(/^\d{3}-\d{2}-\d{4}$/))),
+        get bar() {
+            return z.nullish(z.lazy((): any => zBar));
+        },
+        get baz() {
+            return z.nullish(z.array(z.lazy((): any => zFoo)));
+        },
+        qux: z._default(z.nullish(z.int().check(z.gt(0))), 0)
+    }),
+    z.null()
+]), null);
+
+/**
+ * This is Bar schema.
+ */
+export const zBar = z.object({
+    foo: z.nullish(zFoo)
+});
+
+/**
+ * This is Foo parameter.
+ */
+export const zFoo2 = z.string();
+
+export const zFoo3 = z.object({
+    foo: z.nullish(zBar)
+});
+
+export const zPatchFooData = z.object({
+    body: z.object({
+        foo: z.nullish(z.string())
+    }),
+    path: z.nullish(z.never()),
+    query: z.nullish(z.object({
+        foo: z.nullish(z.string()),
+        bar: z.nullish(zBar),
+        baz: z.nullish(z.object({
+            baz: z.nullish(z.string())
+        })),
+        qux: z.nullish(z.iso.date()),
+        quux: z.nullish(z.iso.datetime())
+    }))
+});
+
+export const zPostFooData = z.object({
+    body: zFoo3,
+    path: z.nullish(z.never()),
+    query: z.nullish(z.never())
+});
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v3/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v3/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..243b28a5e1
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v3/validators-nullish/zod.gen.ts
@@ -0,0 +1,60 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod/v3';
+
+export const zBaz = z.string().regex(/foo\nbar/).readonly().default('baz');
+
+export const zQux = z.record(z.object({
+    qux: z.string().nullish()
+}));
+
+/**
+ * This is Foo schema.
+ */
+export const zFoo: z.ZodTypeAny = z.union([
+    z.object({
+        foo: z.string().regex(/^\d{3}-\d{2}-\d{4}$/).nullish(),
+        bar: z.lazy(() => zBar).nullish(),
+        baz: z.array(z.lazy(() => zFoo)).nullish(),
+        qux: z.number().int().gt(0).nullish().default(0)
+    }),
+    z.null()
+]).default(null);
+
+/**
+ * This is Bar schema.
+ */
+export const zBar = z.object({
+    foo: zFoo.nullish()
+});
+
+/**
+ * This is Foo parameter.
+ */
+export const zFoo2 = z.string();
+
+export const zFoo3 = z.object({
+    foo: zBar.nullish()
+});
+
+export const zPatchFooData = z.object({
+    body: z.object({
+        foo: z.string().nullish()
+    }),
+    path: z.never().nullish(),
+    query: z.object({
+        foo: z.string().nullish(),
+        bar: zBar.nullish(),
+        baz: z.object({
+            baz: z.string().nullish()
+        }).nullish(),
+        qux: z.string().date().nullish(),
+        quux: z.string().datetime().nullish()
+    }).nullish()
+});
+
+export const zPostFooData = z.object({
+    body: zFoo3,
+    path: z.never().nullish(),
+    query: z.never().nullish()
+});
diff --git a/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v4/validators-nullish/zod.gen.ts b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v4/validators-nullish/zod.gen.ts
new file mode 100644
index 0000000000..e78ad99469
--- /dev/null
+++ b/packages/openapi-ts-tests/zod/v4/__snapshots__/3.1.x/v4/validators-nullish/zod.gen.ts
@@ -0,0 +1,64 @@
+// This file is auto-generated by @hey-api/openapi-ts
+
+import { z } from 'zod';
+
+export const zBaz = z.string().regex(/foo\nbar/).readonly().default('baz');
+
+export const zQux = z.record(z.string(), z.object({
+    qux: z.nullish(z.string())
+}));
+
+/**
+ * This is Foo schema.
+ */
+export const zFoo = z.union([
+    z.object({
+        foo: z.nullish(z.string().regex(/^\d{3}-\d{2}-\d{4}$/)),
+        get bar() {
+            return z.nullish(z.lazy((): any => zBar));
+        },
+        get baz() {
+            return z.nullish(z.array(z.lazy((): any => zFoo)));
+        },
+        qux: z.nullish(z.int().gt(0)).default(0)
+    }),
+    z.null()
+]).default(null);
+
+/**
+ * This is Bar schema.
+ */
+export const zBar = z.object({
+    foo: z.nullish(zFoo)
+});
+
+/**
+ * This is Foo parameter.
+ */
+export const zFoo2 = z.string();
+
+export const zFoo3 = z.object({
+    foo: z.nullish(zBar)
+});
+
+export const zPatchFooData = z.object({
+    body: z.object({
+        foo: z.nullish(z.string())
+    }),
+    path: z.nullish(z.never()),
+    query: z.nullish(z.object({
+        foo: z.nullish(z.string()),
+        bar: z.nullish(zBar),
+        baz: z.nullish(z.object({
+            baz: z.nullish(z.string())
+        })),
+        qux: z.nullish(z.iso.date()),
+        quux: z.nullish(z.iso.datetime())
+    }))
+});
+
+export const zPostFooData = z.object({
+    body: zFoo3,
+    path: z.nullish(z.never()),
+    query: z.nullish(z.never())
+});
diff --git a/packages/openapi-ts-tests/zod/v4/test/3.0.x.test.ts b/packages/openapi-ts-tests/zod/v4/test/3.0.x.test.ts
index b9c080a5f2..f5a122ceb7 100644
--- a/packages/openapi-ts-tests/zod/v4/test/3.0.x.test.ts
+++ b/packages/openapi-ts-tests/zod/v4/test/3.0.x.test.ts
@@ -48,6 +48,20 @@ for (const zodVersion of zodVersions) {
         }),
         description: 'generates validator schemas',
       },
+      {
+        config: createConfig({
+          input: 'validators.json',
+          output: 'validators-nullish',
+          plugins: [
+            {
+              compatibilityVersion: zodVersion.compatibilityVersion,
+              name: 'zod',
+              useNullish: true,
+            },
+          ],
+        }),
+        description: 'generates validator schemas with nullish',
+      },
     ];
 
     it.each(scenarios)('$description', async ({ config }) => {
diff --git a/packages/openapi-ts-tests/zod/v4/test/3.1.x.test.ts b/packages/openapi-ts-tests/zod/v4/test/3.1.x.test.ts
index 8d67fe7e23..5953f4cad3 100644
--- a/packages/openapi-ts-tests/zod/v4/test/3.1.x.test.ts
+++ b/packages/openapi-ts-tests/zod/v4/test/3.1.x.test.ts
@@ -55,6 +55,20 @@ for (const zodVersion of zodVersions) {
         }),
         description: 'generates validator schemas',
       },
+      {
+        config: createConfig({
+          input: 'validators.yaml',
+          output: 'validators-nullish',
+          plugins: [
+            {
+              compatibilityVersion: zodVersion.compatibilityVersion,
+              name: 'zod',
+              useNullish: true,
+            },
+          ],
+        }),
+        description: 'generates validator schemas with nullish',
+      },
       {
         config: createConfig({
           input: 'validators.yaml',
diff --git a/packages/openapi-ts/src/plugins/zod/config.ts b/packages/openapi-ts/src/plugins/zod/config.ts
index 6fc57bc03b..8f6082b974 100644
--- a/packages/openapi-ts/src/plugins/zod/config.ts
+++ b/packages/openapi-ts/src/plugins/zod/config.ts
@@ -14,6 +14,7 @@ export const defaultConfig: ZodPlugin['Config'] = {
     comments: true,
     exportFromIndex: false,
     metadata: false,
+    useNullish: false,
   },
   handler,
   name: 'zod',
diff --git a/packages/openapi-ts/src/plugins/zod/constants.ts b/packages/openapi-ts/src/plugins/zod/constants.ts
index 58875dacaa..340755dbd2 100644
--- a/packages/openapi-ts/src/plugins/zod/constants.ts
+++ b/packages/openapi-ts/src/plugins/zod/constants.ts
@@ -1,6 +1,8 @@
 // TODO: this is inaccurate, it combines identifiers for all supported versions
 export const identifiers = {
+  ZodMiniNullish: 'ZodMiniNullish',
   ZodMiniOptional: 'ZodMiniOptional',
+  ZodNullish: 'ZodNullish',
   ZodOptional: 'ZodOptional',
   _default: '_default',
   and: 'and',
@@ -39,6 +41,7 @@ export const identifiers = {
   never: 'never',
   null: 'null',
   nullable: 'nullable',
+  nullish: 'nullish',
   number: 'number',
   object: 'object',
   optional: 'optional',
diff --git a/packages/openapi-ts/src/plugins/zod/mini/plugin.ts b/packages/openapi-ts/src/plugins/zod/mini/plugin.ts
index f4092b3724..3b635292a5 100644
--- a/packages/openapi-ts/src/plugins/zod/mini/plugin.ts
+++ b/packages/openapi-ts/src/plugins/zod/mini/plugin.ts
@@ -139,8 +139,11 @@ export const irSchemaToAst = ({
     }
 
     if (optional) {
-      ast.expression = $(z).attr(identifiers.optional).call(ast.expression);
-      ast.typeName = identifiers.ZodMiniOptional;
+      const method = plugin.config.useNullish ? identifiers.nullish : identifiers.optional;
+      ast.expression = $(z).attr(method).call(ast.expression);
+      ast.typeName = plugin.config.useNullish
+        ? identifiers.ZodMiniNullish
+        : identifiers.ZodMiniOptional;
     }
 
     if (schema.default !== undefined) {
diff --git a/packages/openapi-ts/src/plugins/zod/types.ts b/packages/openapi-ts/src/plugins/zod/types.ts
index 83ec136639..52fbb1f949 100644
--- a/packages/openapi-ts/src/plugins/zod/types.ts
+++ b/packages/openapi-ts/src/plugins/zod/types.ts
@@ -338,6 +338,14 @@ export type UserConfig = Plugin.Name<'zod'> &
             enabled?: boolean;
           };
     };
+    /**
+     * Use `.nullish()` instead of `.optional()` for non-required object
+     * properties? When enabled, non-required properties will accept both
+     * `null` and `undefined` values.
+     *
+     * @default false
+     */
+    useNullish?: boolean;
     /**
      * Configuration for webhook-specific Zod schemas.
      *
@@ -550,6 +558,14 @@ export type Config = Plugin.Name<'zod'> &
         case: Casing;
       };
     };
+    /**
+     * Use `.nullish()` instead of `.optional()` for non-required object
+     * properties? When enabled, non-required properties will accept both
+     * `null` and `undefined` values.
+     *
+     * @default false
+     */
+    useNullish: boolean;
     /**
      * Configuration for webhook-specific Zod schemas.
      *
diff --git a/packages/openapi-ts/src/plugins/zod/v3/plugin.ts b/packages/openapi-ts/src/plugins/zod/v3/plugin.ts
index dc272312dd..4b737351a4 100644
--- a/packages/openapi-ts/src/plugins/zod/v3/plugin.ts
+++ b/packages/openapi-ts/src/plugins/zod/v3/plugin.ts
@@ -131,7 +131,8 @@ export const irSchemaToAst = ({
     }
 
     if (optional) {
-      ast.expression = ast.expression.attr(identifiers.optional).call();
+      const method = plugin.config.useNullish ? identifiers.nullish : identifiers.optional;
+      ast.expression = ast.expression.attr(method).call();
     }
 
     if (schema.default !== undefined) {
diff --git a/packages/openapi-ts/src/plugins/zod/v4/plugin.ts b/packages/openapi-ts/src/plugins/zod/v4/plugin.ts
index 40df25da0d..6bb3e1e34d 100644
--- a/packages/openapi-ts/src/plugins/zod/v4/plugin.ts
+++ b/packages/openapi-ts/src/plugins/zod/v4/plugin.ts
@@ -142,8 +142,9 @@ export const irSchemaToAst = ({
     }
 
     if (optional) {
-      ast.expression = $(z).attr(identifiers.optional).call(ast.expression);
-      ast.typeName = identifiers.ZodOptional;
+      const method = plugin.config.useNullish ? identifiers.nullish : identifiers.optional;
+      ast.expression = $(z).attr(method).call(ast.expression);
+      ast.typeName = plugin.config.useNullish ? identifiers.ZodNullish : identifiers.ZodOptional;
     }
 
     if (schema.default !== undefined) {