diff --git a/include/openthread/link.h b/include/openthread/link.h
index ded1a1e21..f091126be 100644
--- a/include/openthread/link.h
+++ b/include/openthread/link.h
@@ -191,7 +191,7 @@ typedef struct otMacCounters
     /**
      * The total number of unique other MAC frame transmission requests.
      *
-     * This counter is currently unused.
+     * This counter is currently used for counting out-of-band frames.
      *
      */
     uint32_t mTxOther;
diff --git a/src/core/mac/mac.cpp b/src/core/mac/mac.cpp
index b10cb564b..d65bc80f9 100644
--- a/src/core/mac/mac.cpp
+++ b/src/core/mac/mac.cpp
@@ -1369,6 +1369,8 @@ void Mac::HandleTransmitDone(TxFrame &aFrame, RxFrame *aAckFrame, otError aError
 #endif
 
     case kOperationTransmitOutOfBandFrame:
+        // count Oob frames
+        mCounters.mTxOther++;
         FinishOperation();
         PerformNextOperation();
         break;