diff --git a/news.d/bugfix/1357.windows.md b/news.d/bugfix/1357.windows.md
new file mode 100644
index 000000000..7cc78a791
--- /dev/null
+++ b/news.d/bugfix/1357.windows.md
@@ -0,0 +1 @@
+Do not consider extended scan codes in Windows keyboard capture.
diff --git a/plover/oslayer/windows/keyboardcontrol.py b/plover/oslayer/windows/keyboardcontrol.py
index 14067456d..8dddf8998 100644
--- a/plover/oslayer/windows/keyboardcontrol.py
+++ b/plover/oslayer/windows/keyboardcontrol.py
@@ -102,6 +102,11 @@ class INPUT(ctypes.Structure):
 INPUT_MOUSE = 0
 INPUT_KEYBOARD = 1
 
+KF_EXTENDED = 0x0100
+LLKHF_EXTENDED = KF_EXTENDED >> 8
+LLKHF_LOWER_IL_INJECTED = 0x0002
+LLKHF_INJECTED = 0x0010
+
 
 # Process utils code code based on psutil implementation.
 
@@ -318,7 +323,10 @@ def _run(self):
         passthrough_down_keys = set()
 
         def on_key(pressed, event):
-            if event.flags & 0x10:
+            if event.flags & LLKHF_EXTENDED:
+                return False
+
+            if event.flags & LLKHF_INJECTED:
                 # Ignore simulated events (e.g. from KeyboardEmulation).
                 return False
             if event.vkCode in PASSTHROUGH_KEYS: