diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index a8792f4..8134be2 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -6,8 +6,16 @@ jobs:
   test:
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}
+    defaults:
+      run:
+        shell: ${{ contains(matrix.os, 'windows') && 'msys2 {0}' || 'bash -e {0}' }}
     steps:
     - uses: actions/checkout@v7
+    - uses: msys2/setup-msys2@v2
+      if: runner.os == 'Windows'
+      with:
+        msystem: CLANG64
+        install: mingw-w64-clang-x86_64-clang mingw-w64-clang-x86_64-dlfcn mingw-w64-clang-x86_64-uv  # clang for scons, dlopen for the filters
     - run: ./test.sh
diff --git a/SConstruct b/SConstruct
index 7b8fa4e..14a8305 100644
--- a/SConstruct
+++ b/SConstruct
@@ -1,10 +1,12 @@
 import os
 import platform
 import subprocess
+import sys
 import sysconfig
 import numpy as np
 import eigen
 
+WINDOWS = platform.system() == "Windows"
 arch = subprocess.check_output(["uname", "-m"], encoding='utf8').rstrip()
 
 common = ''
@@ -38,8 +40,12 @@ env = Environment(
   CXXFLAGS="-std=c++1z",
   CPPPATH=cpppath,
   REDNOSE_ROOT=Dir("#").abspath,
-  tools=["default", "cython", "rednose_filter"],
+  tools=["mingw" if WINDOWS else "default", "cython", "rednose_filter"],  # the default tool picks MSVC on Windows
 )
+if WINDOWS:
+  env["CC"], env["CXX"] = "clang", "clang++"  # the mingw tool assumes gcc
+  env["SHLIBPREFIX"] = "lib"  # the mingw tool drops the prefix ekf_load expects
+  env.Append(LINKFLAGS=["-static"])  # libc++ into the DLLs so they load outside the MSYS2 shell
 
 # Cython build enviroment
 envCython = env.Clone()
@@ -48,6 +54,10 @@ envCython["CCFLAGS"] += ["-Wno-#warnings", "-Wno-cpp", "-Wno-shadow", "-Wno-depr
 envCython["LIBS"] = []
 if platform.system() == "Darwin":
   envCython["LINKFLAGS"] = ["-bundle", "-undefined", "dynamic_lookup"]
+elif WINDOWS:
+  envCython["LINKFLAGS"] = ["-shared", "-static"]
+  envCython["LIBPATH"] += [os.path.join(sys.base_prefix, "libs")]
+  envCython["LIBS"] = [f"python{sys.version_info.major}{sys.version_info.minor}"]
 elif arch == "aarch64":
   envCython["LINKFLAGS"] = ["-shared"]
   envCython["LIBS"] = [os.path.basename(python_path)]
diff --git a/pyproject.toml b/pyproject.toml
index eadb653..9d70c44 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -46,3 +46,13 @@ flake8-implicit-str-concat.allow-multiline = false
 [tool.ty.rules]
 unresolved-import = "ignore"  # Cython-compiled modules (.pyx) and dynamic SCons exports
 unresolved-attribute = "ignore"  # Cython-backed filter attributes
+
+# --- TODO REMOVE AFTER DEPENDENCY PR MERGES (commaai/dependencies#107): fork-only index of the comma-deps Windows wheels until PyPI has them; not for upstream ---
+[[tool.uv.index]]
+name = "comma-deps-windows"
+url = "https://github.com/AmyJeanes/commaai-dependencies/releases/download/windows-post116/index.html"
+format = "flat"
+explicit = true
+
+[tool.uv.sources]
+comma-deps-eigen = [{ index = "comma-deps-windows", marker = "sys_platform == 'win32'" }]
diff --git a/rednose/helpers/__init__.py b/rednose/helpers/__init__.py
index 3acc14a..e826507 100644
--- a/rednose/helpers/__init__.py
+++ b/rednose/helpers/__init__.py
@@ -16,7 +16,7 @@ def write_code(folder, name, code, header):
 
 
 def load_code(folder, name):
-  shared_ext = "dylib" if platform.system() == "Darwin" else "so"
+  shared_ext = "dylib" if platform.system() == "Darwin" else "dll" if platform.system() == "Windows" else "so"
   shared_fn = os.path.join(folder, f"lib{name}.{shared_ext}")
   header_fn = os.path.join(folder, f"{name}.h")
 
diff --git a/rednose/helpers/ekf_load.cc b/rednose/helpers/ekf_load.cc
index 882b0b4..b1c7114 100644
--- a/rednose/helpers/ekf_load.cc
+++ b/rednose/helpers/ekf_load.cc
@@ -26,6 +26,8 @@ void ekf_load_and_register(const std::string& ekf_directory, const std::string&
 
 #ifdef __APPLE__
   std::string dylib_ext = ".dylib";
+#elif defined(_WIN32)
+  std::string dylib_ext = ".dll";
 #else
   std::string dylib_ext = ".so";
 #endif
diff --git a/site_scons/site_tools/cython.py b/site_scons/site_tools/cython.py
index 702a6e9..59370e2 100644
--- a/site_scons/site_tools/cython.py
+++ b/site_scons/site_tools/cython.py
@@ -70,5 +70,11 @@ def generate(env):
 
   create_builder(env)
 
+  # Python imports extension modules as .pyd on Windows; the SConscripts name them .so
+  if env["PLATFORM"] == "win32":
+    def pyd_emitter(target, source, env):
+      return [env.File(str(t)[:-3] + ".pyd") if str(t).endswith(".so") else t for t in target], source
+    env.Append(PROGEMITTER=[pyd_emitter])
+
 def exists(env):
   return True
diff --git a/site_scons/site_tools/rednose_filter.py b/site_scons/site_tools/rednose_filter.py
index a3f8a9a..7958627 100644
--- a/site_scons/site_tools/rednose_filter.py
+++ b/site_scons/site_tools/rednose_filter.py
@@ -1,4 +1,5 @@
 import platform
+import sys
 
 import eigen
 from SCons.Script import Dir, File
@@ -9,8 +10,9 @@ def compile_single_filter(env, target, filter_gen_script, output_dir, extra_gen_
   extra_generated_files = [File(f'{output_dir}/{x}') for x in extra_gen_artifacts]
   generator_file = File(filter_gen_script)
 
+  # the interpreter running SCons has the deps; cmd.exe cannot start a script by its shebang
   env.Command(generated_src_files + extra_generated_files,
-              [generator_file] + script_deps, f"{File(generator_file).relpath} {target} {Dir(output_dir).relpath}")
+              [generator_file] + script_deps, f'"{sys.executable}" {File(generator_file).relpath} {target} {Dir(output_dir).relpath}')
 
   generated_cc_file = File(generated_src_files[:1])