diff --git a/.github/workflows/test-windows.yml b/.github/workflows/test-windows.yml
index 2669d42fd..4a2b79cfd 100644
--- a/.github/workflows/test-windows.yml
+++ b/.github/workflows/test-windows.yml
@@ -8,9 +8,19 @@ jobs:
     runs-on: windows-2016
     strategy:
       matrix:
-        python-version: ["3.5.4", "3.6.8", "3.7.4"]
+        python-version:
+          - "3.5.4"
+          - "3.6.8"
+          - "3.7.4"
+        platform:
+          - name: "x86"
+            vars: "x86"
+            msbuild: "Win32"
+          - name: "x64"
+            vars: "x86_amd64"
+            msbuild: "x64"
     
-    name: Python ${{ matrix.python-version }} x86
+    name: Python ${{ matrix.python-version }} ${{ matrix.platform.name }}
     
     steps:
     - uses: actions/checkout@v1
@@ -27,7 +37,7 @@ jobs:
         python.exe $env:GITHUB_WORKSPACE\winbuild\build_dep.py
         # .\build_deps.cmd
       env:
-        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\x86
+        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\${{ matrix.platform.name }}
         EXECUTABLE: bin\python.exe
       shell: pwsh
 
@@ -37,7 +47,7 @@ jobs:
         set INCLIB=%GITHUB_WORKSPACE%\winbuild\depends\msvcr10-x32
         set BUILD=%GITHUB_WORKSPACE%\winbuild\build
         cd /D %BUILD%\jpeg-9c
-        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 8.1
+        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" ${{ matrix.platform.vars }} 8.1
         echo on
         nmake -nologo -f makefile.vc setup-vc6
         nmake -nologo -f makefile.vc clean
@@ -51,7 +61,7 @@ jobs:
         set INCLIB=%GITHUB_WORKSPACE%\winbuild\depends\msvcr10-x32
         set BUILD=%GITHUB_WORKSPACE%\winbuild\build
         cd /D %BUILD%\zlib-1.2.11
-        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 8.1
+        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" ${{ matrix.platform.vars }} 8.1
         echo on
         nmake -nologo -f win32\Makefile.msc clean
         nmake -nologo -f win32\Makefile.msc zlib.lib
@@ -65,7 +75,7 @@ jobs:
         set INCLIB=%GITHUB_WORKSPACE%\winbuild\depends\msvcr10-x32
         set BUILD=%GITHUB_WORKSPACE%\winbuild\build
         cd /D %BUILD%\tiff-4.0.10
-        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 8.1
+        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" ${{ matrix.platform.vars }} 8.1
         echo on
         copy %GITHUB_WORKSPACE%\winbuild\nmake.opt nmake.opt
         nmake -nologo -f makefile.vc clean
@@ -80,13 +90,13 @@ jobs:
         set INCLIB=%GITHUB_WORKSPACE%\winbuild\depends\msvcr10-x32
         set BUILD=%GITHUB_WORKSPACE%\winbuild\build
         cd /D %BUILD%\libwebp-1.0.3
-        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 8.1
+        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" ${{ matrix.platform.vars }} 8.1
         echo on
         rmdir /S /Q output\release-static
-        nmake -nologo -f Makefile.vc CFG=release-static RTLIBCFG=static OBJDIR=output ARCH=x86 all
+        nmake -nologo -f Makefile.vc CFG=release-static RTLIBCFG=static OBJDIR=output ARCH=${{ matrix.platform.name }} all
         mkdir %INCLIB%\webp
         copy /Y /B src\webp\*.h %INCLIB%\webp
-        copy /Y /B output\release-static\x86\lib\* %INCLIB%
+        copy /Y /B output\release-static\${{ matrix.platform.name }}\lib\* %INCLIB%
 
     - name: Build dependencies / freetype
       run: |
@@ -96,16 +106,16 @@ jobs:
         set INCLIB=%GITHUB_WORKSPACE%\winbuild\depends\msvcr10-x32
         set BUILD=%GITHUB_WORKSPACE%\winbuild\build
         cd /D %BUILD%\freetype-2.10.1
-        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 8.1
+        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" ${{ matrix.platform.vars }} 8.1
         echo on
         rmdir /S /Q objs
         set DefaultPlatformToolset=v140
         set VCTargetsPath=C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\VC\VCTargets
         set MSBUILD="C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\MSBuild.exe"
-        %MSBUILD% builds\windows\vc2010\freetype.sln /t:Build /p:Configuration="Release" /p:Platform=Win32 /m
+        %MSBUILD% builds\windows\vc2010\freetype.sln /t:Build /p:Configuration="Release" /p:Platform=${{ matrix.platform.msbuild }} /m
         xcopy /Y /E /Q include %INCLIB%
-        copy /Y /B objs\Win32\Release\freetype.dll %INCLIB%
-        copy /Y /B objs\Win32\Release\freetype.lib %INCLIB%
+        copy /Y /B objs\${{ matrix.platform.msbuild }}\Release\freetype.dll %INCLIB%
+        copy /Y /B objs\${{ matrix.platform.msbuild }}\Release\freetype.lib %INCLIB%
 
     - name: Build dependencies / lcms2
       if: false
@@ -116,13 +126,13 @@ jobs:
         set INCLIB=%GITHUB_WORKSPACE%\winbuild\depends\msvcr10-x32
         set BUILD=%GITHUB_WORKSPACE%\winbuild\build
         cd /D %BUILD%\lcms2-2.7
-        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 8.1
+        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" ${{ matrix.platform.vars }} 8.1
         echo on
         rmdir /S /Q Lib
         rmdir /S /Q Projects\VC2015\Release
         set VCTargetsPath=C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\VC\VCTargets
         set MSBUILD="C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\15.0\Bin\MSBuild.exe"
-        %MSBUILD% Projects\VC2015\lcms2.sln /t:Clean;lcms2_static /p:Configuration="Release" /p:Platform=Win32 /m
+        %MSBUILD% Projects\VC2015\lcms2.sln /t:Clean;lcms2_static /p:Configuration="Release" /p:Platform=${{ matrix.platform.msbuild }} /m
         xcopy /Y /E /Q include %INCLIB%
         copy /Y /B Lib\MS\*.lib %INCLIB%
 
@@ -132,7 +142,7 @@ jobs:
         set INCLIB=%GITHUB_WORKSPACE%\winbuild\depends\msvcr10-x32
         set BUILD=%GITHUB_WORKSPACE%\winbuild\build
         cd /D %BUILD%\openjpeg-2.3.1msvcr10-x32
-        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 8.1
+        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" ${{ matrix.platform.vars }} 8.1
         echo on
         cmake.exe -DBUILD_THIRDPARTY:BOOL=OFF -DBUILD_SHARED_LIBS:BOOL=OFF -DCMAKE_BUILD_TYPE=Release -G "NMake Makefiles" .
         nmake -nologo -f Makefile clean
@@ -147,15 +157,14 @@ jobs:
         set INCLIB=%GITHUB_WORKSPACE%\winbuild\depends\msvcr10-x32
         set BUILD=%GITHUB_WORKSPACE%\winbuild\build
         cd /D %BUILD%\ghostscript-9.27
-        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 8.1
+        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" ${{ matrix.platform.vars }} 8.1
         echo on
         set MSVC_VERSION=14
         set RCOMP="C:\Program Files (x86)\Microsoft SDKs\Windows\v7.1A\Bin\RC.Exe"
+        if "${{ matrix.platform.name }}"=="x64" set WIN64=""
         nmake -nologo -f psi\msvc.mak
         rem Add bin to PATH variable: Copy to INCLIB, then add INCLIB to PATH in Test step.
         copy /Y /B bin\* %INCLIB%
-      env:
-        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\x86
 
     - name: Build Pillow
       run: |
@@ -166,19 +175,19 @@ jobs:
         set DISTUTILS_USE_SDK=1
         set LIB=%INCLIB%;%PYTHON%\tcl
         set INCLUDE=%INCLIB%;%GITHUB_WORKSPACE%\depends\tcl86\include;%INCLUDE%
-        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 8.1
+        call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" ${{ matrix.platform.vars }} 8.1
         set BLDOPT=install
         %PYTHON%\%EXECUTABLE% setup.py build_ext --add-imaging-libs=msvcrt install
         %PYTHON%\%EXECUTABLE% -c "from PIL import _webp;import os, shutil;shutil.copy(r'%INCLIB%\freetype.dll', os.path.dirname(_webp.__file__));"
         %PYTHON%\%EXECUTABLE% selftest.py --installed
       env:
-        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\x86
+        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\${{ matrix.platform.name }}
         EXECUTABLE: python.exe
 
     - name: pip install pytest pytest-cov codecov
       run: '%PYTHON%\%PIP% install pytest pytest-cov codecov'
       env:
-        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\x86
+        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\${{ matrix.platform.name }}
         PIP: Scripts\pip.exe
     
     - name: Test Pillow
@@ -189,7 +198,7 @@ jobs:
         cd /D %GITHUB_WORKSPACE%
         %PYTHON%\%EXECUTABLE% -m pytest -vx --cov PIL --cov-report term --cov-report xml Tests
       env:
-        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\x86
+        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\${{ matrix.platform.name }}
         EXECUTABLE: python.exe
     
     - name: Upload coverage
@@ -197,6 +206,6 @@ jobs:
         cd /D %GITHUB_WORKSPACE%
         %PYTHON%\%CODECOV% --file coverage.xml --name %PYTHON%
       env:
-        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\x86
+        PYTHON: C:\hostedtoolcache\windows\Python\${{ matrix.python-version }}\${{ matrix.platform.name }}
         CODECOV: Scripts\codecov.exe