diff --git a/src/core/thread/network_data_tlvs.hpp b/src/core/thread/network_data_tlvs.hpp
index 273c89550..b5ac530c4 100644
--- a/src/core/thread/network_data_tlvs.hpp
+++ b/src/core/thread/network_data_tlvs.hpp
@@ -1128,7 +1128,10 @@ public:
      * @retval TRUE   If the TLV appears to be well-formed.
      * @retval FALSE  If the TLV does not appear to be well-formed.
      */
-    bool IsValid(void) const { return GetLength() >= sizeof(*this) - sizeof(NetworkDataTlv); }
+    bool IsValid(void) const
+    {
+        return (GetLength() >= sizeof(*this) - sizeof(NetworkDataTlv)) && (GetContextId() != 0);
+    }
 
     /**
      * Indicates whether or not the Compress flag is set.