diff --git a/config.def.h b/config.def.h
index dfc94e1..0c09c4d 100644
--- a/config.def.h
+++ b/config.def.h
@@ -67,6 +67,9 @@ static const int THUMB_SIZE = 3;
 #endif
 #ifdef _MAPPINGS_CONFIG
 
+/* Following modifiers (NumLock | CapsLock) will be ignored when processing keybindings */
+static const int ignore_mask = Mod2Mask | LockMask;
+
 /* keyboard mappings for image and thumbnail mode: */
 static const keymap_t keys[] = {
 	/* modifiers    key               function              argument */
diff --git a/main.c b/main.c
index 52062ca..7c58594 100644
--- a/main.c
+++ b/main.c
@@ -566,7 +566,7 @@ end:
 	redraw();
 }
 
-#define MODMASK(mask) ((mask) & (ShiftMask|ControlMask|Mod1Mask))
+#define MODMASK(mask) ((mask) & ~ignore_mask)
 
 void on_keypress(XKeyEvent *kev)
 {