diff --git a/teensy4/usb_serial.c b/teensy4/usb_serial.c
index e23593e2..4e169b6a 100644
--- a/teensy4/usb_serial.c
+++ b/teensy4/usb_serial.c
@@ -36,7 +36,6 @@
 #include "avr/pgmspace.h" // for PROGMEM, DMAMEM, FASTRUN
 
 #include "debug/printf.h"
-#include "core_pins.h"
 
 // defined by usb_dev.h -> usb_desc.h
 #if defined(CDC_STATUS_INTERFACE) && defined(CDC_DATA_INTERFACE)
diff --git a/teensy4/usb_serial.h b/teensy4/usb_serial.h
index 6254a436..c6888197 100644
--- a/teensy4/usb_serial.h
+++ b/teensy4/usb_serial.h
@@ -30,6 +30,7 @@
 
 #pragma once
 
+#include "core_pins.h"
 #include "usb_desc.h"
 #include <stdint.h>