diff --git a/arch/arm/src/stm32/stm32_serial.c b/arch/arm/src/stm32/stm32_serial.c
index 6152d5795d7..644c810817e 100644
--- a/arch/arm/src/stm32/stm32_serial.c
+++ b/arch/arm/src/stm32/stm32_serial.c
@@ -3006,7 +3006,7 @@ void stm32_serial_dma_poll(void)
  * Name: up_putc
  *
  * Description:
- *   Provide priority, low-level access to support OS debug  writes
+ *   Provide priority, low-level access to support OS debug writes
  *
  ****************************************************************************/