diff --git a/src/core/mac/mac.cpp b/src/core/mac/mac.cpp
index aaffbecdf..9a03156d0 100644
--- a/src/core/mac/mac.cpp
+++ b/src/core/mac/mac.cpp
@@ -106,6 +106,8 @@ Mac::Mac(ThreadNetif &aThreadNetif):
         mExtAddress.m8[i] = otPlatRandomGet();
     }
 
+    mExtAddress.m8[0] &= ~1; // always remove multicast bit
+
     memset(&mCounters, 0, sizeof(otMacCounters));
 
     SetExtendedPanId(sExtendedPanidInit);