diff --git a/.github/workflows/build-polars-ols.yml b/.github/workflows/build-polars-ols.yml
new file mode 100644
index 000000000000..2d5dc786f547
--- /dev/null
+++ b/.github/workflows/build-polars-ols.yml
@@ -0,0 +1,147 @@
+# SPDX-FileCopyrightText: 2026 The RISE Project
+# SPDX-License-Identifier: MIT
+---
+# This workflow is based on the `linux` and `linux_tests` jobs of
+# https://github.com/azmyrajab/polars_ols/blob/v0.3.5/.github/workflows/CI.yml
+name: Build polars-ols wheels (riscv64)
+
+on:
+  workflow_dispatch:
+    inputs:
+      version:
+        description: 'Version glob to (re)build; empty builds every version of docs/packages/polars-ols.yaml not released yet'
+        required: false
+        default: ''
+  pull_request:
+    branches: [main]
+    paths:
+      - '.github/workflows/build-polars-ols.yml'
+      - 'docs/packages/polars-ols.yaml'
+      - 'patches/polars-ols/**'
+  push:
+    branches: [main]
+    paths:
+      - '.github/workflows/build-polars-ols.yml'
+      - 'docs/packages/polars-ols.yaml'
+      - 'patches/polars-ols/**'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+env:
+  MANYLINUX_RISCV64_IMAGE: quay.io/pypa/manylinux_2_39_riscv64
+  # rust-toolchain.toml floats on "nightly"; this is the nightly upstream's 0.3.5
+  # wheels were built with (2024-08-25), which its pinned crates still compile on.
+  RUST_TOOLCHAIN: nightly-2024-08-25
+
+jobs:
+  setup:
+    uses: $/.github/workflows/_setup.yml
+    with:
+      package: polars-ols
+      version: ${{ inputs.version }}
+
+  build_wheels:
+    needs: [setup]
+    if: needs.setup.outputs.versions != '[]'
+    name: Build polars-ols ${{ matrix.version }} cp38-abi3-manylinux_riscv64
+    runs-on: ubuntu-24.04-riscv
+    timeout-minutes: 360
+    strategy:
+      fail-fast: false
+      matrix:
+        version: ${{ fromJSON(needs.setup.outputs.versions) }}
+
+    env:
+      POLARS_OLS_VERSION: ${{ matrix.version }}
+
+    steps:
+      - name: Checkout polars_ols v${{ env.POLARS_OLS_VERSION }}
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
+        with:
+          repository: azmyrajab/polars_ols
+          ref: v${{ env.POLARS_OLS_VERSION }}
+          persist-credentials: false
+
+      - name: Checkout python-wheels
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
+        with:
+          path: python-wheels
+          sparse-checkout: patches/polars-ols
+          persist-credentials: false
+
+      - name: Apply patches
+        run: git apply -v python-wheels/patches/polars-ols/${{ env.POLARS_OLS_VERSION }}/*.patch
+
+      - name: Build and test wheel
+        uses: pypa/cibuildwheel@1828c10ab37f080699c7b81cea34097c684a7074  # v4.2.0
+        with:
+          output-dir: wheelhouse/
+        env:
+          # abi3-py38 gives one wheel, built on cp312 and re-tested on cp313. cp314:
+          # statsmodels has no riscv64 cp314 wheel; cp314t: pyo3 0.21 has no free-threading.
+          # musllinux is dropped: rustup.rs ships no riscv64 musl toolchain.
+          CIBW_BUILD: cp312-manylinux_riscv64 cp313-manylinux_riscv64
+          CIBW_MANYLINUX_RISCV64_IMAGE: ${{ env.MANYLINUX_RISCV64_IMAGE }}
+          CIBW_BEFORE_ALL_LINUX: >-
+            curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs |
+            sh -s -- -y --profile minimal --default-toolchain ${{ env.RUST_TOOLCHAIN }}
+          # gotcha 76: pyproject.toml's build-system.requires pins an unused "polars"
+          # (maturin builds the Rust polars crate from crates.io, never imports the
+          # Python package), which resolves to polars-runtime-32 and falls back to a
+          # from-source build needing a newer Rust than RUST_TOOLCHAIN. Skip resolving
+          # build-system.requires entirely instead of patching the pin.
+          CIBW_BEFORE_BUILD_LINUX: pip install "maturin>=1.0,<2.0"
+          CIBW_BUILD_FRONTEND: "pip; args: --no-build-isolation"
+          CIBW_ENVIRONMENT_LINUX: >-
+            PATH="$PATH:$HOME/.cargo/bin"
+            RUSTUP_TOOLCHAIN=${{ env.RUST_TOOLCHAIN }}
+            RUSTFLAGS="-Dwarnings"
+            PIP_EXTRA_INDEX_URL=https://pypi.riseproject.dev/simple/
+          # gotcha 67: PyPI's newer numpy/pandas sdists outrun the registry; pandas 3.1.0 fails to compile on riscv64.
+          CIBW_TEST_ENVIRONMENT: PIP_ONLY_BINARY=numpy,pandas,pyarrow,scipy,statsmodels,scikit-learn,polars-runtime-32
+          # tests/requirements-test.txt, minus maturin/pyperf; the 0.3.5 suite calls
+          # Expr.flatten, removed in polars 2.0.
+          CIBW_TEST_REQUIRES: polars[pandas,pyarrow]<2 numpy pytest statsmodels scikit-learn
+          CIBW_TEST_SOURCES: tests
+          CIBW_TEST_COMMAND: >-
+            python -c "import polars_ols._polars_ols as m; assert m.__file__.endswith('.so'), m.__file__" &&
+            python -m pytest -v tests
+
+      - name: Check the licence made it into the wheel
+        run: |
+          python3 - wheelhouse/*.whl <<'EOF'
+          import sys, zipfile
+          for whl in sys.argv[1:]:
+              assert "-cp38-abi3-manylinux_" in whl and whl.endswith("_riscv64.whl"), whl
+              names = zipfile.ZipFile(whl).namelist()
+              assert any(n.endswith("dist-info/licenses/LICENSE") for n in names), names
+              print(whl, "ok")
+          EOF
+
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
+        with:
+          name: polars-ols-${{ env.POLARS_OLS_VERSION }}-cp38-abi3-manylinux_riscv64
+          path: wheelhouse/*.whl
+          if-no-files-found: error
+
+  publish:
+    name: Publish polars-ols ${{ matrix.version }}
+    needs: [setup, build_wheels]
+    if: needs.setup.outputs.versions != '[]'
+    strategy:
+      fail-fast: false
+      matrix:
+        version: ${{ fromJSON(needs.setup.outputs.versions) }}
+    permissions:
+      contents: write
+      pull-requests: write
+    uses: $/.github/workflows/_publish-wheel.yml
+    secrets:
+      app-private-key: ${{ secrets.RISEPROJECT_APP_PRIVATE_KEY }}
+    with:
+      artifact-pattern: polars-ols-${{ matrix.version }}-*-manylinux_riscv64
diff --git a/docs/packages/polars-ols.yaml b/docs/packages/polars-ols.yaml
new file mode 100644
index 000000000000..297c7cf59b66
--- /dev/null
+++ b/docs/packages/polars-ols.yaml
@@ -0,0 +1,6 @@
+package-name: polars-ols
+source-code: https://github.com/azmyrajab/polars_ols
+license: MIT
+versions:
+- version: 0.3.5
+  patched: true
diff --git a/patches/polars-ols/0.3.5/0001-Cargo-build-faer-and-pulp-without-nightly-on-riscv64.patch b/patches/polars-ols/0.3.5/0001-Cargo-build-faer-and-pulp-without-nightly-on-riscv64.patch
new file mode 100644
index 000000000000..3591defa8d8e
--- /dev/null
+++ b/patches/polars-ols/0.3.5/0001-Cargo-build-faer-and-pulp-without-nightly-on-riscv64.patch
@@ -0,0 +1,51 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Ludovic Henry <git@ludovic.dev>
+Date: Thu, 22 Oct 2026 00:00:00 +0000
+Subject: [PATCH] Cargo: build faer and pulp without "nightly" on riscv64
+
+Every non-ARM target enables pulp's and faer's "nightly" features.
+faer's "nightly" turns on faer-entity/gemm/gemm-common "nightly", which
+all end up enabling pulp/nightly. On riscv64, pulp 0.18.22 then does
+
+    #[cfg(all(feature = "nightly", target_arch = "riscv64"))]
+    pub use core::arch::riscv64::*;
+
+without adding #![feature(riscv_ext_intrinsics)], so the crate fails
+to compile on the nightly toolchain:
+
+    error[E0658]: use of unstable library feature 'riscv_ext_intrinsics'
+      --> pulp-0.18.22/src/core_arch/mod.rs:24:13
+
+pulp has no riscv64 SIMD paths for "nightly" to switch on (its
+re-export is never used on riscv64), so on riscv64 build faer and pulp
+without "nightly", as Cargo.toml already does for ARM. faer keeps the
+same "std", "rayon", "serde", "rand", "npy" features. The dependency
+graph is unchanged, so Cargo.lock still resolves with --locked; on
+x86_64 the feature set is identical to before.
+
+Upstream-Status: To upstream [not submitted from this automated port run; needs a pull request against azmyrajab/polars_ols]
+
+Signed-off-by: Ludovic Henry <git@ludovic.dev>
+---
+ Cargo.toml | 7 ++++++-
+ 1 file changed, 6 insertions(+), 1 deletion(-)
+
+diff --git a/Cargo.toml b/Cargo.toml
+--- a/Cargo.toml
++++ b/Cargo.toml
+@@ -40,7 +40,12 @@ ndarray-linalg = {version = "*"}
+ faer = { version = "*" }  # don't allow nightly for ARM due to issues with NEON support
+ faer-ext = { version = "*", features = ["ndarray"] }
+
+-[target.'cfg(not(target_arch = "arm"))'.dependencies]
++[target.'cfg(target_arch = "riscv64")'.dependencies]
++pulp = { version = "0.18.22" }  # pulp's "nightly" re-exports core::arch::riscv64 without enabling riscv_ext_intrinsics
++faer = { version = "*", features = ["std", "rayon", "serde", "rand", "npy"] }
++faer-ext = { version = "*", features = ["ndarray"] }
++
++[target.'cfg(not(any(target_arch = "arm", target_arch = "riscv64")))'.dependencies]
+ pulp = { version = "0.18.22", features = ["nightly"] }
+ faer = { version = "*", features = ["std", "rayon", "serde", "rand", "npy", "nightly"] }
+ faer-ext = { version = "*", features = ["ndarray"] }
+--
+2.43.0
diff --git a/patches/polars-ols/0.3.5/0002-tests-cast-insert_nulls-values-to-float.patch b/patches/polars-ols/0.3.5/0002-tests-cast-insert_nulls-values-to-float.patch
new file mode 100644
index 000000000000..2a158af319d9
--- /dev/null
+++ b/patches/polars-ols/0.3.5/0002-tests-cast-insert_nulls-values-to-float.patch
@@ -0,0 +1,38 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Ludovic Henry <git@ludovic.dev>
+Date: Thu, 22 Oct 2026 00:00:00 +0000
+Subject: [PATCH] tests: cast insert_nulls values to float
+
+_make_data(add_missing=True) runs every column, including the Int64
+"group" column, through map_elements(insert_nulls,
+return_dtype=pl.Float64), and insert_nulls hands back the original int.
+polars up to 1.35 silently cast those ints to Float64; polars 1.36 and
+later reject them while building the Series:
+
+    polars.exceptions.SchemaError: unexpected value while building
+    Series of type Float64; found value of type Int64: 0
+
+so test_non_contiguous fails before reaching polars-ols. The oldest
+polars available for riscv64 is 1.39, so no installable version still
+accepts it. Return float(val), which is the cast older polars did
+implicitly; the generated data is unchanged.
+
+Upstream-Status: To upstream [not submitted from this automated port run; needs a pull request against azmyrajab/polars_ols]
+
+Signed-off-by: Ludovic Henry <git@ludovic.dev>
+---
+ tests/test_ols.py | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/tests/test_ols.py b/tests/test_ols.py
+--- a/tests/test_ols.py
++++ b/tests/test_ols.py
+@@ -42,7 +42,7 @@
+     if add_missing:
+
+         def insert_nulls(val):
+-            return None if rng.random() < 0.1 else val
++            return None if rng.random() < 0.1 else float(val)
+
+         columns = missing_columns or df.columns
+         df = df.with_columns(