diff --git a/pyproject.toml b/pyproject.toml
index b0dd7a2e..df084e16 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,7 +8,13 @@ dependencies = [
   "PyWinCtl >=0.0.42", # py.typed
   "keyboard @ git+https://github.com/boppreh/keyboard.git", # Fix install on macos and linux-ci https://github.com/boppreh/keyboard/pull/568
   "numpy >=2.3.2", # Python 3.14 support # TODO: Bump when 3.15 wheels
-  "opencv-contrib-python-headless >=5.0", # v4.13: glibc 2.28 wheels (for aarch); v5 restored sdist
+  # v4.13: glibc 2.28 wheels (for aarch); v5 restored sdist
+  "opencv-contrib-python-headless >=5.0; sys_platform != 'win32' or platform_machine != 'ARM64'",
+  # Windows ARM64 has no opencv wheel (any version) so it source-builds the sdist.
+  # v5 sdist fails to build there (opencv-python setup.py expects an ffmpeg dll that
+  # isn't provided for win-arm64). Pin to the last 4.x that builds until win-arm64
+  # wheels ship: https://github.com/opencv/opencv-python/pull/1143
+  "opencv-contrib-python-headless ==4.11.*; sys_platform == 'win32' and platform_machine == 'ARM64'",
   "packaging >=20.0", # py.typed
   "tomli-w >=1.1.0", # Typing fixes
 
diff --git a/uv.lock b/uv.lock
index c8540eed..20766cc1 100644
--- a/uv.lock
+++ b/uv.lock
@@ -83,7 +83,8 @@ dependencies = [
     { name = "keyboard" },
     { name = "levenshtein" },
     { name = "numpy" },
-    { name = "opencv-contrib-python-headless" },
+    { name = "opencv-contrib-python-headless", version = "4.11.0.86", source = { registry = "https://pypi.org/simple" }, marker = "platform_machine == 'ARM64' and sys_platform == 'win32'" },
+    { name = "opencv-contrib-python-headless", version = "5.0.0.93", source = { registry = "https://pypi.org/simple" }, marker = "platform_machine != 'ARM64' or sys_platform != 'win32'" },
     { name = "packaging" },
     { name = "pillow", marker = "sys_platform != 'win32'" },
     { name = "pyautogui" },
@@ -129,7 +130,8 @@ requires-dist = [
     { name = "keyboard", git = "https://github.com/boppreh/keyboard.git" },
     { name = "levenshtein", specifier = ">=0.27.3" },
     { name = "numpy", specifier = ">=2.3.2" },
-    { name = "opencv-contrib-python-headless", specifier = ">=5.0" },
+    { name = "opencv-contrib-python-headless", marker = "platform_machine != 'ARM64' or sys_platform != 'win32'", specifier = ">=5.0" },
+    { name = "opencv-contrib-python-headless", marker = "platform_machine == 'ARM64' and sys_platform == 'win32'", specifier = "==4.11.*" },
     { name = "packaging", specifier = ">=20.0" },
     { name = "pillow", marker = "sys_platform == 'linux'", specifier = ">=12.2.0" },
     { name = "pyautogui", specifier = ">=0.9.52" },
@@ -353,10 +355,29 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/fd/6a/d3a169aaf8536cf228d56a09e04bcb713a2fe4410d4e2105b9419b5a9c89/numpy-2.5.0-cp314-cp314t-win_arm64.whl", hash = "sha256:016623417bb330d719d579daf2d6b9a01ddc52e41a9ed61a47f39fde46dcd865", size = 10686451, upload-time = "2026-06-21T20:57:49.313Z" },
 ]
 
+[[package]]
+name = "opencv-contrib-python-headless"
+version = "4.11.0.86"
+source = { registry = "https://pypi.org/simple" }
+resolution-markers = [
+    "python_full_version >= '3.15' and platform_machine == 'ARM64' and sys_platform == 'win32'",
+    "python_full_version < '3.15' and platform_machine == 'ARM64' and sys_platform == 'win32'",
+]
+dependencies = [
+    { name = "numpy" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/53/cc/295e9a4e783ca71ba1b8fbd34e51bc603eba4611afcfc7de1b09b2d6ed8d/opencv-contrib-python-headless-4.11.0.86.tar.gz", hash = "sha256:839319098a73264c580c97cb1ca835f7fce3d30e4fa9fa6d4d0618fff551be0b", size = 150579288, upload-time = "2025-01-16T13:54:11.763Z" }
+
 [[package]]
 name = "opencv-contrib-python-headless"
 version = "5.0.0.93"
 source = { registry = "https://pypi.org/simple" }
+resolution-markers = [
+    "python_full_version >= '3.15' and sys_platform == 'linux'",
+    "python_full_version < '3.15' and sys_platform == 'linux'",
+    "python_full_version >= '3.15' and platform_machine != 'ARM64' and sys_platform == 'win32'",
+    "python_full_version < '3.15' and platform_machine != 'ARM64' and sys_platform == 'win32'",
+]
 dependencies = [
     { name = "numpy" },
 ]