diff --git a/src/keyboard/ergodox/teensy-2-0.c b/src/keyboard/ergodox/teensy-2-0.c
index d88f44f..f09d033 100644
--- a/src/keyboard/ergodox/teensy-2-0.c
+++ b/src/keyboard/ergodox/teensy-2-0.c
@@ -8,6 +8,7 @@
 
 
 #include <avr/io.h>
+#include <util/delay.h>
 #include "lib/data-types.h"
 #define TWI_FREQ 400000
 #include "lib/twi.h"