diff --git a/contrib/automation/hgautomation/cli.py b/contrib/automation/hgautomation/cli.py
--- a/contrib/automation/hgautomation/cli.py
+++ b/contrib/automation/hgautomation/cli.py
@@ -158,7 +158,7 @@
 
         windows.synchronize_hg(SOURCE_ROOT, revision, instance)
 
-        for py_version in ("2.7", "3.7", "3.8", "3.9"):
+        for py_version in ("2.7", "3.7", "3.8", "3.9", "3.10"):
             for arch in ("x86", "x64"):
                 windows.purge_hg(winrm_client)
                 windows.build_wheel(
@@ -377,7 +377,7 @@
     sp.add_argument(
         '--python-version',
         help='Python version to build for',
-        choices={'2.7', '3.7', '3.8', '3.9'},
+        choices={'2.7', '3.7', '3.8', '3.9', '3.10'},
         nargs='*',
         default=['3.8'],
     )
@@ -501,7 +501,7 @@
     sp.add_argument(
         '--python-version',
         help='Python version to use',
-        choices={'2.7', '3.5', '3.6', '3.7', '3.8', '3.9'},
+        choices={'2.7', '3.5', '3.6', '3.7', '3.8', '3.9', '3.10'},
         default='2.7',
     )
     sp.add_argument(
diff --git a/contrib/automation/hgautomation/windows.py b/contrib/automation/hgautomation/windows.py
--- a/contrib/automation/hgautomation/windows.py
+++ b/contrib/automation/hgautomation/windows.py
@@ -129,6 +129,8 @@
 WHEEL_FILENAME_PYTHON38_X64 = 'mercurial-{version}-cp38-cp38-win_amd64.whl'
 WHEEL_FILENAME_PYTHON39_X86 = 'mercurial-{version}-cp39-cp39-win32.whl'
 WHEEL_FILENAME_PYTHON39_X64 = 'mercurial-{version}-cp39-cp39-win_amd64.whl'
+WHEEL_FILENAME_PYTHON310_X86 = 'mercurial-{version}-cp310-cp310-win32.whl'
+WHEEL_FILENAME_PYTHON310_X64 = 'mercurial-{version}-cp310-cp310-win_amd64.whl'
 
 EXE_FILENAME_PYTHON2_X86 = 'Mercurial-{version}-x86-python2.exe'
 EXE_FILENAME_PYTHON2_X64 = 'Mercurial-{version}-x64-python2.exe'
@@ -480,6 +482,8 @@
         dist_path / WHEEL_FILENAME_PYTHON38_X64.format(version=version),
         dist_path / WHEEL_FILENAME_PYTHON39_X86.format(version=version),
         dist_path / WHEEL_FILENAME_PYTHON39_X64.format(version=version),
+        dist_path / WHEEL_FILENAME_PYTHON310_X86.format(version=version),
+        dist_path / WHEEL_FILENAME_PYTHON310_X64.format(version=version),
     )
 
 
@@ -493,6 +497,8 @@
         dist_path / WHEEL_FILENAME_PYTHON38_X64.format(version=version),
         dist_path / WHEEL_FILENAME_PYTHON39_X86.format(version=version),
         dist_path / WHEEL_FILENAME_PYTHON39_X64.format(version=version),
+        dist_path / WHEEL_FILENAME_PYTHON310_X86.format(version=version),
+        dist_path / WHEEL_FILENAME_PYTHON310_X64.format(version=version),
         dist_path / EXE_FILENAME_PYTHON2_X86.format(version=version),
         dist_path / EXE_FILENAME_PYTHON2_X64.format(version=version),
         dist_path / EXE_FILENAME_PYTHON3_X86.format(version=version),
diff --git a/contrib/install-windows-dependencies.ps1 b/contrib/install-windows-dependencies.ps1
--- a/contrib/install-windows-dependencies.ps1
+++ b/contrib/install-windows-dependencies.ps1
@@ -34,6 +34,11 @@
 $PYTHON39_X64_URL = "https://www.python.org/ftp/python/3.9.9/python-3.9.9-amd64.exe"
 $PYTHON39_x64_SHA256 = "137d59e5c0b01a8f1bdcba08344402ae658c81c6bf03b6602bd8b4e951ad0714"
 
+$PYTHON310_x86_URL = "https://www.python.org/ftp/python/3.10.0/python-3.10.0.exe"
+$PYTHON310_x86_SHA256 = "ea896eeefb1db9e12fb89ec77a6e28c9fe52b4a162a34c85d9688be2ec2392e8"
+$PYTHON310_X64_URL = "https://www.python.org/ftp/python/3.10.0/python-3.10.0-amd64.exe"
+$PYTHON310_x64_SHA256 = "cb580eb7dc55f9198e650f016645023e8b2224cf7d033857d12880b46c5c94ef"
+
 # PIP 19.2.3.
 $PIP_URL = "https://github.com/pypa/get-pip/raw/309a56c5fd94bd1134053a541cb4657a4e47e09d/get-pip.py"
 $PIP_SHA256 = "57e3643ff19f018f8a00dfaa6b7e4620e3c1a7a2171fd218425366ec006b3bfe"
@@ -132,6 +137,8 @@
     Secure-Download $PYTHON38_x64_URL ${prefix}\assets\python38-x64.exe $PYTHON38_x64_SHA256
     Secure-Download $PYTHON39_x86_URL ${prefix}\assets\python39-x86.exe $PYTHON39_x86_SHA256
     Secure-Download $PYTHON39_x64_URL ${prefix}\assets\python39-x64.exe $PYTHON39_x64_SHA256
+    Secure-Download $PYTHON310_x86_URL ${prefix}\assets\python310-x86.exe $PYTHON310_x86_SHA256
+    Secure-Download $PYTHON310_x64_URL ${prefix}\assets\python310-x64.exe $PYTHON310_x64_SHA256
     Secure-Download $PIP_URL ${pip} $PIP_SHA256
     Secure-Download $VS_BUILD_TOOLS_URL ${prefix}\assets\vs_buildtools.exe $VS_BUILD_TOOLS_SHA256
     Secure-Download $INNO_SETUP_URL ${prefix}\assets\InnoSetup.exe $INNO_SETUP_SHA256
@@ -146,6 +153,8 @@
 #    Install-Python3 "Python 3.8 64-bit" ${prefix}\assets\python38-x64.exe ${prefix}\python38-x64 ${pip}
     Install-Python3 "Python 3.9 32-bit" ${prefix}\assets\python39-x86.exe ${prefix}\python39-x86 ${pip}
     Install-Python3 "Python 3.9 64-bit" ${prefix}\assets\python39-x64.exe ${prefix}\python39-x64 ${pip}
+    Install-Python3 "Python 3.10 32-bit" ${prefix}\assets\python310-x86.exe ${prefix}\python310-x86 ${pip}
+    Install-Python3 "Python 3.10 64-bit" ${prefix}\assets\python310-x64.exe ${prefix}\python310-x64 ${pip}
 
     Write-Output "installing Visual Studio 2017 Build Tools and SDKs"
     Invoke-Process ${prefix}\assets\vs_buildtools.exe "--quiet --wait --norestart --nocache --channelUri https://aka.ms/vs/15/release/channel --add Microsoft.VisualStudio.Workload.MSBuildTools --add Microsoft.VisualStudio.Component.Windows10SDK.17763 --add Microsoft.VisualStudio.Workload.VCTools --add Microsoft.VisualStudio.Component.Windows10SDK --add Microsoft.VisualStudio.Component.VC.140"