diff --git a/.github/workflows/build-simplejpeg.yml b/.github/workflows/build-simplejpeg.yml
new file mode 100644
index 000000000..7fdc8dcdd
--- /dev/null
+++ b/.github/workflows/build-simplejpeg.yml
@@ -0,0 +1,103 @@
+# SPDX-FileCopyrightText: 2026 The RISE Project
+# SPDX-License-Identifier: MIT
+---
+# This workflow is based on upstream's own cibuildwheel-driven
+# https://github.com/jfolz/simplejpeg/blob/1.9.0/.github/workflows/build_wheels.yml, narrowed to
+# Linux riscv64.
+name: Build simplejpeg wheels (riscv64)
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'simplejpeg version to build (git tag, e.g. 1.9.0)'
+        required: true
+        default: '1.9.0'
+  pull_request:
+    paths:
+      - '.github/workflows/build-simplejpeg.yml'
+      - 'patches/simplejpeg/**'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ inputs.version || '1.9.0' }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read  # to fetch code (actions/checkout)
+
+env:
+  SIMPLEJPEG_VERSION: ${{ inputs.version || '1.9.0' }}
+  MANYLINUX_RISCV64_IMAGE: quay.io/pypa/manylinux_2_39_riscv64
+
+jobs:
+  setup:
+    uses: $/.github/workflows/_setup.yml
+
+  build_wheels:
+    needs: [setup]
+    name: Build simplejpeg ${{ inputs.version || '1.9.0' }} ${{ matrix.python }}-manylinux_riscv64
+    runs-on: ubuntu-24.04-riscv
+    strategy:
+      fail-fast: false
+      matrix:
+        python: ["cp312", "cp313", "cp314"]
+
+    steps:
+      - name: Checkout simplejpeg v${{ env.SIMPLEJPEG_VERSION }}
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
+        with:
+          repository: jfolz/simplejpeg
+          ref: ${{ env.SIMPLEJPEG_VERSION }}
+          persist-credentials: false
+
+      - name: Checkout python-wheels
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
+        with:
+          path: python-wheels
+          persist-credentials: false
+
+      - name: Patch simplejpeg source
+        run: git apply python-wheels/patches/simplejpeg/${{ env.SIMPLEJPEG_VERSION }}/*.patch
+
+      - name: Build wheels
+        uses: pypa/cibuildwheel@1828c10ab37f080699c7b81cea34097c684a7074  # v4.2.0
+        with:
+          output-dir: wheelhouse/
+          only: ${{ matrix.python }}-manylinux_riscv64
+        env:
+          CIBW_MANYLINUX_RISCV64_IMAGE: ${{ env.MANYLINUX_RISCV64_IMAGE }}
+          # Upstream's before-all installs nasm to assemble libjpeg-turbo's x86 SIMD kernels;
+          # the patch above disables SIMD on riscv64 (no such kernels), so it's not needed here.
+          CIBW_BEFORE_ALL_LINUX: "true"
+          CIBW_BEFORE_BUILD: curl -fsSL -o {project}/LICENSE.libjpeg-turbo https://raw.githubusercontent.com/libjpeg-turbo/libjpeg-turbo/3.1.2/LICENSE.md
+          CIBW_ENVIRONMENT: >-
+            PIP_ONLY_BINARY=:all:
+            PIP_EXTRA_INDEX_URL=https://pypi.riseproject.dev/simple/
+
+      - name: Check the wheel contents
+        run: |
+          python3 - wheelhouse/*.whl <<'EOF'
+          import sys, zipfile
+          for whl in sys.argv[1:]:
+              names = zipfile.ZipFile(whl).namelist()
+              assert any(n.startswith("simplejpeg/_jpeg") and n.endswith(".so") for n in names), whl
+              licenses = {n.rsplit("/", 1)[1] for n in names if ".dist-info/licenses/" in n} - {""}
+              assert licenses == {"LICENSE", "LICENSE.libjpeg-turbo"}, (whl, licenses)
+              print(whl, "ok")
+          EOF
+
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
+        with:
+          name: simplejpeg-${{ env.SIMPLEJPEG_VERSION }}-${{ matrix.python }}-manylinux_riscv64
+          path: wheelhouse/*.whl
+          if-no-files-found: error
+
+  publish:
+    name: Publish simplejpeg ${{ inputs.version || '1.9.0' }}
+    needs: [setup, build_wheels]
+    permissions:
+      contents: write
+      pull-requests: write
+    uses: $/.github/workflows/_publish-wheel.yml
+    with:
+      artifact-pattern: simplejpeg-${{ inputs.version || '1.9.0' }}-*-manylinux_riscv64
diff --git a/patches/simplejpeg/1.9.0/0001-setup.py-dont-require-SIMD-on-riscv64.patch b/patches/simplejpeg/1.9.0/0001-setup.py-dont-require-SIMD-on-riscv64.patch
new file mode 100644
index 000000000..ac33d7523
--- /dev/null
+++ b/patches/simplejpeg/1.9.0/0001-setup.py-dont-require-SIMD-on-riscv64.patch
@@ -0,0 +1,33 @@
+From afa7c8bd316bf4f53f02ccf55916b75618fd229a Mon Sep 17 00:00:00 2001
+From: Ludovic Henry <git@ludovic.dev>
+Date: Mon, 7 Sep 2026 21:02:32 +0200
+Subject: [PATCH] setup.py: don't require SIMD when building libjpeg-turbo on
+ riscv64
+
+libjpeg-turbo's simd/CMakeLists.txt only ships SIMD kernels for
+x86/x86-64/Arm/MIPS/PowerPC; REQUIRE_SIMD=1 turns the unsupported-arch
+warning into a hard cmake configure failure on riscv64. The option's
+own default (off) already falls back to a portable non-SIMD build with
+just a warning, so only force it on for the architectures that have a
+kernel.
+
+Upstream-Status: Inappropriate [libjpeg-turbo has no riscv64 SIMD kernels]
+
+Signed-off-by: Ludovic Henry <git@ludovic.dev>
+---
+ setup.py | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/setup.py b/setup.py
+index bfcbf6b..52d9035 100644
+--- a/setup.py
++++ b/setup.py
+@@ -165,7 +165,7 @@ class cmake_build_ext(build_ext):
+             *flags,
+             '-DWITH_CRT_DLL=1',  # fixes https://bugs.python.org/issue24872
+             '-DENABLE_SHARED=0',
+-            '-DREQUIRE_SIMD=1',
++            '-DREQUIRE_SIMD=' + ('0' if ARCH == 'riscv64' else '1'),
+             '-DCMAKE_POSITION_INDEPENDENT_CODE=ON',
+         ], env=env)
+