diff --git a/github/dependency_graph_test.go b/github/dependency_graph_test.go
index 1bae03b9559..cc6b66981a0 100644
--- a/github/dependency_graph_test.go
+++ b/github/dependency_graph_test.go
@@ -76,3 +76,363 @@ func TestDependencyGraphService_GetSBOM(t *testing.T) {
 		return resp, err
 	})
 }
+
+func TestSBOM_Marshal(t *testing.T) {
+	testJSONMarshal(t, &SBOM{}, `{}`)
+
+	u := &SBOM{
+		SBOM: &SBOMInfo{
+			SPDXID:       Ptr("SPDXRef-DOCUMENT"),
+			SPDXVersion:  Ptr("SPDX-2.3"),
+			CreationInfo: &CreationInfo{Creators: []string{"GitHub"}},
+			Name:         Ptr("owner/repo"),
+		},
+	}
+
+	want := `{
+		"sbom": {
+			"SPDXID": "SPDXRef-DOCUMENT",
+			"spdxVersion": "SPDX-2.3",
+			"creationInfo": {
+				"creators": [
+					"GitHub"
+				]
+			},
+			"name": "owner/repo"
+		}
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestCreationInfo_Marshal(t *testing.T) {
+	testJSONMarshal(t, &CreationInfo{}, `{}`)
+
+	created := Timestamp{time.Date(2024, time.January, 2, 3, 4, 5, 0, time.UTC)}
+	u := &CreationInfo{
+		Created:  &created,
+		Creators: []string{"GitHub", "go-github"},
+	}
+
+	want := `{
+		"created": "2024-01-02T03:04:05Z",
+		"creators": [
+			"GitHub",
+			"go-github"
+		]
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestRepoDependencies_Marshal(t *testing.T) {
+	testJSONMarshal(t, &RepoDependencies{}, `{}`)
+
+	u := &RepoDependencies{
+		SPDXID:           Ptr("SPDXRef-Package"),
+		Name:             Ptr("pkg:golang/github.com/google/go-github"),
+		VersionInfo:      Ptr("v88.0.0"),
+		DownloadLocation: Ptr("NOASSERTION"),
+		FilesAnalyzed:    Ptr(false),
+		LicenseConcluded: Ptr("Apache-2.0"),
+		LicenseDeclared:  Ptr("Apache-2.0"),
+		ExternalRefs: []*PackageExternalRef{
+			{
+				ReferenceCategory: "PACKAGE-MANAGER",
+				ReferenceType:     "purl",
+				ReferenceLocator:  "pkg:golang/github.com/google/go-github@v88.0.0",
+			},
+		},
+	}
+
+	want := `{
+		"SPDXID": "SPDXRef-Package",
+		"name": "pkg:golang/github.com/google/go-github",
+		"versionInfo": "v88.0.0",
+		"downloadLocation": "NOASSERTION",
+		"filesAnalyzed": false,
+		"licenseConcluded": "Apache-2.0",
+		"licenseDeclared": "Apache-2.0",
+		"externalRefs": [
+			{
+				"referenceCategory": "PACKAGE-MANAGER",
+				"referenceType": "purl",
+				"referenceLocator": "pkg:golang/github.com/google/go-github@v88.0.0"
+			}
+		]
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestPackageExternalRef_Marshal(t *testing.T) {
+	testJSONMarshal(t, &PackageExternalRef{}, `{
+		"referenceCategory": "",
+		"referenceType": "",
+		"referenceLocator": ""
+	}`)
+
+	u := &PackageExternalRef{
+		ReferenceCategory: "PACKAGE-MANAGER",
+		ReferenceType:     "purl",
+		ReferenceLocator:  "pkg:npm/@actions/core@1.1.9",
+	}
+
+	want := `{
+		"referenceCategory": "PACKAGE-MANAGER",
+		"referenceType": "purl",
+		"referenceLocator": "pkg:npm/@actions/core@1.1.9"
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestSBOMRelationship_Marshal(t *testing.T) {
+	testJSONMarshal(t, &SBOMRelationship{}, `{
+		"spdxElementId": "",
+		"relatedSpdxElement": "",
+		"relationshipType": ""
+	}`)
+
+	u := &SBOMRelationship{
+		SPDXElementID:      "SPDXRef-DOCUMENT",
+		RelatedSPDXElement: "SPDXRef-Package",
+		RelationshipType:   "DESCRIBES",
+	}
+
+	want := `{
+		"spdxElementId": "SPDXRef-DOCUMENT",
+		"relatedSpdxElement": "SPDXRef-Package",
+		"relationshipType": "DESCRIBES"
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestSBOMInfo_Marshal(t *testing.T) {
+	testJSONMarshal(t, &SBOMInfo{}, `{}`)
+
+	created := Timestamp{time.Date(2024, time.January, 2, 3, 4, 5, 0, time.UTC)}
+	u := &SBOMInfo{
+		SPDXID:            Ptr("SPDXRef-DOCUMENT"),
+		SPDXVersion:       Ptr("SPDX-2.3"),
+		CreationInfo:      &CreationInfo{Created: &created, Creators: []string{"GitHub"}},
+		Name:              Ptr("owner/repo"),
+		DataLicense:       Ptr("CC0-1.0"),
+		DocumentDescribes: []string{"SPDXRef-Package"},
+		DocumentNamespace: Ptr("https://github.com/owner/repo/dependency_graph/sbom"),
+		Packages:          []*RepoDependencies{{Name: Ptr("github.com/google/go-github")}},
+		Relationships:     []*SBOMRelationship{{SPDXElementID: "SPDXRef-DOCUMENT", RelatedSPDXElement: "SPDXRef-Package", RelationshipType: "DESCRIBES"}},
+	}
+
+	want := `{
+		"SPDXID": "SPDXRef-DOCUMENT",
+		"spdxVersion": "SPDX-2.3",
+		"creationInfo": {
+			"created": "2024-01-02T03:04:05Z",
+			"creators": [
+				"GitHub"
+			]
+		},
+		"name": "owner/repo",
+		"dataLicense": "CC0-1.0",
+		"documentDescribes": [
+			"SPDXRef-Package"
+		],
+		"documentNamespace": "https://github.com/owner/repo/dependency_graph/sbom",
+		"packages": [
+			{
+				"name": "github.com/google/go-github"
+			}
+		],
+		"relationships": [
+			{
+				"spdxElementId": "SPDXRef-DOCUMENT",
+				"relatedSpdxElement": "SPDXRef-Package",
+				"relationshipType": "DESCRIBES"
+			}
+		]
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestDependencyGraphSnapshotResolvedDependency_Marshal(t *testing.T) {
+	testJSONMarshal(t, &DependencyGraphSnapshotResolvedDependency{}, `{}`)
+
+	u := &DependencyGraphSnapshotResolvedDependency{
+		PackageURL:   Ptr("pkg:npm/@actions/core@1.1.9"),
+		Metadata:     map[string]any{"license": "MIT"},
+		Relationship: Ptr("direct"),
+		Scope:        Ptr("runtime"),
+		Dependencies: []string{"@actions/http-client"},
+	}
+
+	want := `{
+		"package_url": "pkg:npm/@actions/core@1.1.9",
+		"metadata": {
+			"license": "MIT"
+		},
+		"relationship": "direct",
+		"scope": "runtime",
+		"dependencies": [
+			"@actions/http-client"
+		]
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestDependencyGraphSnapshotJob_Marshal(t *testing.T) {
+	testJSONMarshal(t, &DependencyGraphSnapshotJob{}, `{}`)
+
+	u := &DependencyGraphSnapshotJob{
+		Correlator: Ptr("workflow_action"),
+		ID:         Ptr("123456"),
+		HTMLURL:    Ptr("https://github.com/owner/repo/actions/runs/123456"),
+	}
+
+	want := `{
+		"correlator": "workflow_action",
+		"id": "123456",
+		"html_url": "https://github.com/owner/repo/actions/runs/123456"
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestDependencyGraphSnapshotDetector_Marshal(t *testing.T) {
+	testJSONMarshal(t, &DependencyGraphSnapshotDetector{}, `{}`)
+
+	u := &DependencyGraphSnapshotDetector{
+		Name:    Ptr("go-github"),
+		Version: Ptr("v88.0.0"),
+		URL:     Ptr("https://github.com/google/go-github"),
+	}
+
+	want := `{
+		"name": "go-github",
+		"version": "v88.0.0",
+		"url": "https://github.com/google/go-github"
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestDependencyGraphSnapshotManifestFile_Marshal(t *testing.T) {
+	testJSONMarshal(t, &DependencyGraphSnapshotManifestFile{}, `{}`)
+
+	u := &DependencyGraphSnapshotManifestFile{SourceLocation: Ptr("go.mod")}
+
+	want := `{
+		"source_location": "go.mod"
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestDependencyGraphSnapshotManifest_Marshal(t *testing.T) {
+	testJSONMarshal(t, &DependencyGraphSnapshotManifest{}, `{}`)
+
+	u := &DependencyGraphSnapshotManifest{
+		Name:     Ptr("go.mod"),
+		File:     &DependencyGraphSnapshotManifestFile{SourceLocation: Ptr("go.mod")},
+		Metadata: map[string]any{"ecosystem": "go"},
+		Resolved: map[string]*DependencyGraphSnapshotResolvedDependency{
+			"github.com/google/go-github": {
+				PackageURL:   Ptr("pkg:golang/github.com/google/go-github@v88.0.0"),
+				Relationship: Ptr("direct"),
+				Scope:        Ptr("runtime"),
+			},
+		},
+	}
+
+	want := `{
+		"name": "go.mod",
+		"file": {
+			"source_location": "go.mod"
+		},
+		"metadata": {
+			"ecosystem": "go"
+		},
+		"resolved": {
+			"github.com/google/go-github": {
+				"package_url": "pkg:golang/github.com/google/go-github@v88.0.0",
+				"relationship": "direct",
+				"scope": "runtime"
+			}
+		}
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestDependencyGraphSnapshot_Marshal(t *testing.T) {
+	testJSONMarshal(t, &DependencyGraphSnapshot{}, `{"version": 0}`)
+
+	scanned := Timestamp{time.Date(2024, time.January, 2, 3, 4, 5, 0, time.UTC)}
+	u := &DependencyGraphSnapshot{
+		Version:  1,
+		Sha:      Ptr("ce587453ced02b1526dfb4cb910479d431683101"),
+		Ref:      Ptr("refs/heads/main"),
+		Job:      &DependencyGraphSnapshotJob{Correlator: Ptr("workflow_action"), ID: Ptr("123456")},
+		Detector: &DependencyGraphSnapshotDetector{Name: Ptr("go-github"), Version: Ptr("v88.0.0")},
+		Scanned:  &scanned,
+		Metadata: map[string]any{"build": "release"},
+		Manifests: map[string]*DependencyGraphSnapshotManifest{
+			"go.mod": {
+				Name: Ptr("go.mod"),
+				File: &DependencyGraphSnapshotManifestFile{SourceLocation: Ptr("go.mod")},
+			},
+		},
+	}
+
+	want := `{
+		"version": 1,
+		"sha": "ce587453ced02b1526dfb4cb910479d431683101",
+		"ref": "refs/heads/main",
+		"job": {
+			"correlator": "workflow_action",
+			"id": "123456"
+		},
+		"detector": {
+			"name": "go-github",
+			"version": "v88.0.0"
+		},
+		"scanned": "2024-01-02T03:04:05Z",
+		"metadata": {
+			"build": "release"
+		},
+		"manifests": {
+			"go.mod": {
+				"name": "go.mod",
+				"file": {
+					"source_location": "go.mod"
+				}
+			}
+		}
+	}`
+
+	testJSONMarshal(t, u, want)
+}
+
+func TestDependencyGraphSnapshotCreationData_Marshal(t *testing.T) {
+	testJSONMarshal(t, &DependencyGraphSnapshotCreationData{}, `{"id": 0}`)
+
+	createdAt := Timestamp{time.Date(2024, time.January, 2, 3, 4, 5, 0, time.UTC)}
+	u := &DependencyGraphSnapshotCreationData{
+		ID:        12345,
+		CreatedAt: &createdAt,
+		Message:   Ptr("Dependency results for the repo have been successfully updated."),
+		Result:    Ptr("SUCCESS"),
+	}
+
+	want := `{
+		"id": 12345,
+		"created_at": "2024-01-02T03:04:05Z",
+		"message": "Dependency results for the repo have been successfully updated.",
+		"result": "SUCCESS"
+	}`
+
+	testJSONMarshal(t, u, want)
+}