diff --git a/arch/arm/src/tiva/tiva_timer.h b/arch/arm/src/tiva/tiva_timer.h
index 2b16dfb2a88..d1261e9e19f 100644
--- a/arch/arm/src/tiva/tiva_timer.h
+++ b/arch/arm/src/tiva/tiva_timer.h
@@ -892,7 +892,7 @@ static inline void tiva_gptm0_synchronize(uint32_t sync)
  *   devpath - The full path to the timer device.  This should be of the form
  *     /dev/timer0
  *   gptm - General purpose timer number
- *   timeout - Timeout interval in milliseconds. Set to a non-zero value
+ *   timeout - Timeout interval in microseconds. Set to a non-zero value
  *     to enable timeout interrupts
  *   altlck - True: Use alternate clock source.
  *