@@ -141,6 +141,69 @@ jobs:
           bash ../scripts/bench-taskset.sh uv run --all-packages pytest --benchmark-only benchmark/
         working-directory: vortex-python/
 
+  python-windows:
+    name: "Python (windows-x64)"
+    timeout-minutes: 60
+    runs-on: >-
+      ${{ github.repository == 'vortex-data/vortex'
+          && format('runs-on={0}/pool=windows-x64-pre/extras=s3-cache', github.run_id)
+          || 'windows-latest' }}
+    steps:
+      - uses: runs-on/action@v2
+        if: github.repository == 'vortex-data/vortex'
+        with:
+          sccache: s3
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
+      - name: Setup (Windows)
+        run: |
+          echo "C:\rust\cargo\bin" >> $env:GITHUB_PATH
+      - uses: ./.github/actions/setup-prebuild
+        with:
+          enable-sccache: "true"
+      - uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97  # v7
+        with:
+          python-version: "3.11"
+
+      # Mirrors the wheel build in package.yml, which spells the Windows interpreter
+      # `python` because maturin has no `python3.11` executable to resolve there.
+      - name: Build wheel
+        uses: PyO3/maturin-action@e83996d129638aa358a18fbd1dfb82f0b0fb5d3b  # v1
+        with:
+          command: build
+          maturin-version: 1.10.2
+          target: x86_64-pc-windows-msvc
+          args: >
+            --profile ci
+            --manifest-path vortex-python/Cargo.toml
+            --out dist
+            --interpreter python
+        env:
+          # Keep this constant to avoid pyo3 invalidating itself
+          PYO3_ENVIRONMENT_SIGNATURE: "cpython3"
+
+      # rust-test-windows excludes vortex-python, so this is the only check that the
+      # win_amd64 wheel imports and can round-trip a file. Runs outside the checkout so
+      # the repo-root `vortex/` crate directory cannot shadow the installed package.
+      - name: Import and round-trip the wheel
+        shell: bash
+        run: |
+          python -m pip install dist/*.whl
+          cd "$RUNNER_TEMP"
+          python - <<'PY'
+          import pyarrow as pa
+
+          import vortex as vx
+
+          table = pa.table({"a": [1, 2, 3], "b": ["x", "y", "z"]})
+          vx.io.write(table, "smoke.vortex")
+          # Vortex reads utf8 back as string_view, so compare column-wise rather than by table.
+          round_tripped = vx.open("smoke.vortex").to_arrow().read_all()
+          assert round_tripped.column_names == table.column_names
+          assert round_tripped.column("a").to_pylist() == [1, 2, 3]
+          assert round_tripped.column("b").to_pylist() == ["x", "y", "z"]
+          print("vortex", vx.__version__, "round-tripped a file on Windows")
+          PY
+
   # Pins the measurement_id hash that scripts/post-ingest.py uses as the primary key of every
   # benchmarks-database fact row. The golden vectors are a frozen artifact (see the note inside
   # the JSON); this job fails if a change to scripts/_measurement_id.py drifts the hash, which
 
@@ -30,6 +30,7 @@ jobs:
           - { os: macos, runs-on: "macos-15-intel", target: x86_64-apple-darwin }
           - { os: ubuntu, runs-on: "ubuntu-latest", target: aarch64-unknown-linux-gnu }
           - { os: ubuntu, runs-on: "ubuntu-latest", target: x86_64-unknown-linux-gnu }
+          - { os: windows, runs-on: "windows-latest", target: x86_64-pc-windows-msvc }
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
         with:
@@ -46,6 +47,7 @@ jobs:
           tool: cargo-edit@0.13.10
 
       - name: Cargo Set Version
+        shell: bash
         run: |
           cargo set-version --workspace ${{ inputs.version }}
 
@@ -56,8 +58,11 @@ jobs:
       - name: Set Python extension version pins
         env:
           VERSION: ${{ inputs.version }}
+        shell: bash
         run: |
-          python3 - <<'PY'
+          # Not every runner image puts a `python3` on PATH; Windows may only have `python`.
+          PYTHON="$(command -v python3 || command -v python)"
+          "$PYTHON" - <<'PY'
           import os
           import re
           from pathlib import Path
@@ -79,8 +84,9 @@ jobs:
 
       - name: Set up Python
         uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97  # v7
-        # Latest macOS doesn't allow maturin to install stuff into the global Python interpreter
-        if: "${{ matrix.target.runs-on == 'macos-latest' }}"
+        # Latest macOS doesn't allow maturin to install stuff into the global Python interpreter.
+        # Windows has no versioned `python3.11` executable, so pin what `python` resolves to.
+        if: "${{ matrix.target.runs-on == 'macos-latest' || matrix.target.os == 'windows' }}"
         with:
           python-version: "3.11"
 
@@ -96,7 +102,7 @@ jobs:
             --release
             --manifest-path vortex-python/Cargo.toml
             --out dist
-            --interpreter python3.11
+            --interpreter ${{ (matrix.target.os == 'windows' && 'python') || 'python3.11' }}
         env:
           MATURIN_PEP517_USE_BASE_PYTHON: "true"
           # Keep this constant to avoid pyo3 invalidating itself
@@ -131,6 +137,44 @@ jobs:
           retention-days: 7
           if-no-files-found: error
 
+  prepare-java-windows:
+    runs-on: >-
+      ${{ github.repository == 'vortex-data/vortex'
+          && format('runs-on={0}/pool=windows-x64-pre/extras=s3-cache', github.run_id)
+          || 'windows-latest' }}
+    timeout-minutes: 90
+    steps:
+      - uses: runs-on/action@v2
+        if: github.repository == 'vortex-data/vortex'
+        with:
+          sccache: s3
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7
+        with:
+          fetch-depth: 0
+      - uses: actions/setup-java@b6effb05e454b25005698d916606bdc6ffcbf961  # v5
+        with:
+          distribution: "corretto"
+          java-version: "17"
+      - name: Setup (Windows)
+        run: |
+          echo "C:\rust\cargo\bin" >> $env:GITHUB_PATH
+      - uses: ./.github/actions/setup-prebuild
+        with:
+          enable-sccache: ${{ github.repository == 'vortex-data/vortex' && 'true' || 'false' }}
+      - run: cargo build --release --package vortex-jni
+        shell: bash
+      # Cargo names the Windows cdylib `vortex_jni.dll`; the bundled resource keeps the
+      # `lib` prefix used on every other platform so NativeLoader builds a single name.
+      - name: Rename JNI library
+        shell: bash
+        run: cp target/release/vortex_jni.dll target/release/libvortex_jni.dll
+      - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7
+        with:
+          name: "libvortex_jni_x86_64-pc-windows-msvc.zip"
+          path: "target/release/libvortex_jni.dll"
+          retention-days: 7
+          if-no-files-found: error
+
   prepare-java-linux:
     timeout-minutes: 30
     strategy:
@@ -171,7 +215,7 @@ jobs:
           if-no-files-found: error
 
   prepare-all:
-    needs: [prepare-python, prepare-java-macos, prepare-java-linux]
+    needs: [prepare-python, prepare-java-macos, prepare-java-linux, prepare-java-windows]
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
 
@@ -101,9 +101,11 @@ jobs:
           mkdir -p vortex-jni/src/main/resources/native/darwin-aarch64
           mkdir -p vortex-jni/src/main/resources/native/linux-aarch64
           mkdir -p vortex-jni/src/main/resources/native/linux-amd64
+          mkdir -p vortex-jni/src/main/resources/native/win-amd64
           cp ../libvortex_jni_aarch64-apple-darwin.zip/libvortex_jni.dylib ./vortex-jni/src/main/resources/native/darwin-aarch64
           cp ../libvortex_jni_aarch64-unknown-linux-gnu.zip/libvortex_jni.so ./vortex-jni/src/main/resources/native/linux-aarch64
           cp ../libvortex_jni_x86_64-unknown-linux-gnu.zip/libvortex_jni.so ./vortex-jni/src/main/resources/native/linux-amd64
+          cp ../libvortex_jni_x86_64-pc-windows-msvc.zip/libvortex_jni.dll ./vortex-jni/src/main/resources/native/win-amd64
       - name: Build Java
         run: ./gradlew shadowJar
       - name: Publish to Maven Central
 
@@ -32,6 +32,7 @@ The Java bindings are supported on the following architectures:
 * x86_64 Linux
 * ARM64 Linux
 * Apple Silicon macOS
+* x86_64 Windows
 
 They support any Linux distribution with a GLIBC version >= 2.31. This includes
 
 
@@ -27,6 +27,8 @@ The Python bindings require Python 3.11 or newer. Pre-built wheels are available
 * x86_64 Linux
 * ARM64 Linux
 * Apple Silicon macOS
+* x86_64 macOS
+* x86_64 Windows
 
 They support any Linux distribution with a GLIBC version >= 2.17. This includes
 
 
@@ -7,10 +7,10 @@ connector is published to Maven Central in two flavors:
 - `dev.vortex:vortex-spark_2.12` for Spark 3.5.x (Scala 2.12)
 
 Use the `all` classifier JAR (e.g. `vortex-spark_2.13-0.85.0-all.jar`). It is self-contained:
-it bundles the Vortex JNI bindings, native libraries for Linux (x86_64 and aarch64) and macOS
-(aarch64), and relocates its Arrow, Guava, and Jackson dependencies to avoid classpath
-conflicts with Spark. The thin (unclassified) JAR does not work on its own because it
-references relocated classes that only ship in the `all` JAR.
+it bundles the Vortex JNI bindings, native libraries for Linux (x86_64 and aarch64), macOS
+(aarch64), and Windows (x86_64), and relocates its Arrow, Guava, and Jackson dependencies to
+avoid classpath conflicts with Spark. The thin (unclassified) JAR does not work on its own
+because it references relocated classes that only ship in the `all` JAR.
 
 ## Getting Vortex into Spark
 
 
@@ -11,7 +11,7 @@ We provide two interfaces for working with Vortex from Java:
 
 We publish three artifacts out of this repo at CI time to Maven Central Sonatype:
 
-* `vortex-jni` JAR containing the JNI code, plus compiled native libraries for all of the following targets: `aarch64-apple-darwin`, `aarch64-unknown-linux-gnu`, `x86_64-unknown-linux-gnu`
+* `vortex-jni` JAR containing the JNI code, plus compiled native libraries for all of the following targets: `aarch64-apple-darwin`, `aarch64-unknown-linux-gnu`, `x86_64-unknown-linux-gnu`, `x86_64-pc-windows-msvc`
 * `vortex-jni-all` which is the "shadow JAR" containing all of `vortex-jni` as well as all upstream Java dependencies packaged in a single JAR.
 * `vortex-spark` which is the runtime JAR needed for the Vortex Spark bindings
 
 
@@ -1,2 +1,3 @@
+*.dll
 *.dylib
 *.so
@@ -129,7 +129,11 @@ val libExt =
         "win" -> ".dll"
         else -> throw GradleException("Unsupported OS short name: $osShortName")
     }
-val nativeLibrary = rustWorkspaceDir.resolve("target/debug/libvortex_jni$libExt")
+// Cargo emits `vortex_jni.dll` on Windows and `libvortex_jni.{so,dylib}` elsewhere. The
+// bundled resources always use the `lib` prefix so that NativeLoader can build one name.
+val bundledLibraryName = "libvortex_jni$libExt"
+val cargoLibraryName = if (osShortName == "win") "vortex_jni$libExt" else bundledLibraryName
+val nativeLibrary = rustWorkspaceDir.resolve("target/debug/$cargoLibraryName")
 val nativeLibraryDir = "src/main/resources/native/$osShortName-$osArch"
 
 val buildJniLibrary =
@@ -156,7 +160,9 @@ tasks.register<Copy>("makeTestFiles") {
 
     // Only populate the host-arch directory so cross-compiled libs for other
     // architectures (placed by the publish workflow) are preserved.
-    from(nativeLibrary)
+    from(nativeLibrary) {
+        rename { bundledLibraryName }
+    }
     into(nativeLibraryDir)
 }
 
 
@@ -45,6 +45,7 @@ mod serde;
 mod session;
 mod store;
 
+#[cfg(unix)]
 use vortex::io::runtime::BlockingRuntime;
 use vortex::io::runtime::current::CurrentThreadRuntime;
 use vortex::io::runtime::current::CurrentThreadWorkerPool;