diff --git a/.github/workflows/base.yml b/.github/workflows/base.yml
index 93f3fb9..92a8b48 100644
--- a/.github/workflows/base.yml
+++ b/.github/workflows/base.yml
@@ -36,19 +36,31 @@ jobs:
       run: |
         uv venv .venv
 
-    - name: Activate virtual environment
+    - name: Activate virtual environment (Unix)
+      if: runner.os != 'Windows'
       run: |
         source .venv/bin/activate
 
+    - name: Activate virtual environment (Windows)
+      if: runner.os == 'Windows'
+      run: |
+        .venv\Scripts\activate
+
     - name: Install dependencies with uv
       run: |
         uv pip install transformers>=4.0.0
         uv pip install . --system
 
-    - name: Add nanochat to PYTHONPATH
+    - name: Add nanochat to PYTHONPATH (Unix)
+      if: runner.os != 'Windows'
       run: |
         echo "PYTHONPATH=$(pwd):$PYTHONPATH" >> $GITHUB_ENV
 
+    - name: Add nanochat to PYTHONPATH (Windows)
+      if: runner.os == 'Windows'
+      run: |
+        echo "PYTHONPATH=$PWD;$env:PYTHONPATH" >> $env:GITHUB_ENV
+
     - name: Install pytest
       run: |
         python -m pip install pytest