diff --git a/src/cocoa_window.m b/src/cocoa_window.m
index 9d794940..c865c09e 100644
--- a/src/cocoa_window.m
+++ b/src/cocoa_window.m
@@ -1659,14 +1659,15 @@ const char* _glfwGetScancodeNameCocoa(int scancode)
 {
     @autoreleasepool {
 
-    if (scancode < 0 || scancode > 0xff ||
-        _glfw.ns.keycodes[scancode] == GLFW_KEY_UNKNOWN)
+    if (scancode < 0 || scancode > 0xff)
     {
         _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
         return NULL;
     }
 
     const int key = _glfw.ns.keycodes[scancode];
+    if (key == GLFW_KEY_UNKNOWN)
+        return NULL;
 
     UInt32 deadKeyState = 0;
     UniChar characters[4];
diff --git a/src/win32_window.c b/src/win32_window.c
index db3bed6e..917a0f6c 100644
--- a/src/win32_window.c
+++ b/src/win32_window.c
@@ -2223,14 +2223,17 @@ void _glfwSetCursorModeWin32(_GLFWwindow* window, int mode)
 
 const char* _glfwGetScancodeNameWin32(int scancode)
 {
-    if (scancode < 0 || scancode > (KF_EXTENDED | 0xff) ||
-        _glfw.win32.keycodes[scancode] == GLFW_KEY_UNKNOWN)
+    if (scancode < 0 || scancode > (KF_EXTENDED | 0xff))
     {
         _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
         return NULL;
     }
 
-    return _glfw.win32.keynames[_glfw.win32.keycodes[scancode]];
+    const int key = _glfw.win32.keycodes[scancode];
+    if (key == GLFW_KEY_UNKNOWN)
+        return NULL;
+
+    return _glfw.win32.keynames[key];
 }
 
 int _glfwGetKeyScancodeWin32(int key)
diff --git a/src/wl_window.c b/src/wl_window.c
index 8d8f8ab1..f047f44c 100644
--- a/src/wl_window.c
+++ b/src/wl_window.c
@@ -2535,8 +2535,7 @@ void _glfwSetCursorModeWayland(_GLFWwindow* window, int mode)
 
 const char* _glfwGetScancodeNameWayland(int scancode)
 {
-    if (scancode < 0 || scancode > 255 ||
-        _glfw.wl.keycodes[scancode] == GLFW_KEY_UNKNOWN)
+    if (scancode < 0 || scancode > 255)
     {
         _glfwInputError(GLFW_INVALID_VALUE,
                         "Wayland: Invalid scancode %i",
@@ -2545,6 +2544,9 @@ const char* _glfwGetScancodeNameWayland(int scancode)
     }
 
     const int key = _glfw.wl.keycodes[scancode];
+    if (key == GLFW_KEY_UNKNOWN)
+        return NULL;
+
     const xkb_keycode_t keycode = scancode + 8;
     const xkb_layout_index_t layout =
         xkb_state_key_get_layout(_glfw.wl.xkb.state, keycode);
diff --git a/src/x11_window.c b/src/x11_window.c
index 3c76d3a9..c2541b9f 100644
--- a/src/x11_window.c
+++ b/src/x11_window.c
@@ -2901,14 +2901,16 @@ const char* _glfwGetScancodeNameX11(int scancode)
     if (!_glfw.x11.xkb.available)
         return NULL;
 
-    if (scancode < 0 || scancode > 0xff ||
-        _glfw.x11.keycodes[scancode] == GLFW_KEY_UNKNOWN)
+    if (scancode < 0 || scancode > 0xff)
     {
         _glfwInputError(GLFW_INVALID_VALUE, "Invalid scancode %i", scancode);
         return NULL;
     }
 
     const int key = _glfw.x11.keycodes[scancode];
+    if (key == GLFW_KEY_UNKNOWN)
+        return NULL;
+
     const KeySym keysym = XkbKeycodeToKeysym(_glfw.x11.display,
                                              scancode, _glfw.x11.xkb.group, 0);
     if (keysym == NoSymbol)