diff --git a/src/core/thread/thread_netif.hpp b/src/core/thread/thread_netif.hpp
index b974d37b9..c12f77e7d 100644
--- a/src/core/thread/thread_netif.hpp
+++ b/src/core/thread/thread_netif.hpp
@@ -215,7 +215,7 @@ private:
  */
 struct ThreadMessageInfo
 {
-    uint8_t mLinkMargin;     ///< The Link Margin for a received message in dBm.
+    uint8_t mLinkMargin;     ///< The Link Margin for a received message in dB.
     uint8_t mLqi;            ///< The Link Quality Indicator for a received message.
     bool    mSecurityValid;  ///< Link security on all received frames was enabled and passed validation.
 };