diff --git a/arch/risc-v/src/mpfs/mpfs_mpu.c b/arch/risc-v/src/mpfs/mpfs_mpu.c
index 2643c79c0ac7a..4a59f808b1809 100644
--- a/arch/risc-v/src/mpfs/mpfs_mpu.c
+++ b/arch/risc-v/src/mpfs/mpfs_mpu.c
@@ -159,9 +159,10 @@ int mpfs_mpu_set(uintptr_t reg, uintptr_t perm, uintptr_t base,
       return -EACCES;
     }
 
-  /* Base must be word aligned, minimum size is 4K */
+  /* Base must be word aligned,
+   * minimum size is 4K and it has to be power-of-two */
 
-  if ((base & 0x07) != 0 || size < 0x1000)
+  if ((base & 0x07) != 0 || size < 0x1000 || (size & (size - 1)) != 0)
     {
       return -EINVAL;
     }