diff --git a/data/moves/moves.asm b/data/moves/moves.asm
index c95e9d125..f2d3c07d4 100644
--- a/data/moves/moves.asm
+++ b/data/moves/moves.asm
@@ -8,6 +8,7 @@ MACRO move
 	db \5 percent ; accuracy
 	db \6 ; pp
 	db \7 percent ; effect chance
+	assert \6 <= 40, "PP must be 40 or less"
 ENDM
 
 Moves: