diff --git a/data/moves/moves.asm b/data/moves/moves.asm
index b7e5e7af..c32a89cb 100644
--- a/data/moves/moves.asm
+++ b/data/moves/moves.asm
@@ -5,6 +5,7 @@ MACRO move
 	db \4 ; type
 	db \5 percent ; accuracy
 	db \6 ; pp
+	assert \6 <= 40, "PP must be 40 or less"
 ENDM
 
 Moves: