diff --git a/drivers/tee/optee/optee_smc.h b/drivers/tee/optee/optee_smc.h
index c60896cf71cb..73b5e7760d10 100644
--- a/drivers/tee/optee/optee_smc.h
+++ b/drivers/tee/optee/optee_smc.h
@@ -189,7 +189,7 @@ struct optee_smc_call_get_os_revision_result {
  * Have config return register usage:
  * a0	OPTEE_SMC_RETURN_OK
  * a1	Physical address of start of SHM
- * a2	Size of of SHM
+ * a2	Size of SHM
  * a3	Cache settings of memory, as defined by the
  *	OPTEE_SMC_SHM_* values above
  * a4-7	Preserved