diff --git a/drivers/sgp30/sgp30.c b/drivers/sgp30/sgp30.c
index f9897d4f30..e25284ae4e 100644
--- a/drivers/sgp30/sgp30.c
+++ b/drivers/sgp30/sgp30.c
@@ -238,6 +238,7 @@ int sgp30_reset(sgp30_t *dev)
 
 int sgp30_read_serial_number(sgp30_t *dev, uint8_t *buf, size_t len)
 {
+    (void) len;
     assert(dev && buf && (len == SGP30_SERIAL_ID_LEN));
     uint8_t frame[9];
     if (_rx_tx_data(dev, SGP30_CMD_READ_SERIAL, (uint8_t *)frame, sizeof(frame),