diff --git a/include/openthread-types.h b/include/openthread-types.h
index 849ee48cc..cbd19f05b 100644
--- a/include/openthread-types.h
+++ b/include/openthread-types.h
@@ -483,6 +483,7 @@ typedef enum otMeshcopTlvType
     OT_MESHCOP_TLV_NETWORKNAME               = 3,    ///< meshcop Network Name TLV
     OT_MESHCOP_TLV_PSKC                      = 4,    ///< meshcop PSKc TLV
     OT_MESHCOP_TLV_MASTERKEY                 = 5,    ///< meshcop Network Master Key TLV
+    OT_MESHCOP_TLV_NETWORK_KEY_SEQUENCE      = 6,    ///< meshcop Network Key Sequence TLV
     OT_MESHCOP_TLV_MESHLOCALPREFIX           = 7,    ///< meshcop Mesh Local Prefix TLV
     OT_MESHCOP_TLV_STEERING_DATA             = 8,    ///< meshcop Steering Data TLV
     OT_MESHCOP_TLV_BORDER_AGENT_RLOC         = 9,    ///< meshcop Border Agent Locator TLV
diff --git a/src/core/meshcop/joiner.cpp b/src/core/meshcop/joiner.cpp
index ec42c1cf5..29679d0fe 100644
--- a/src/core/meshcop/joiner.cpp
+++ b/src/core/meshcop/joiner.cpp
@@ -373,6 +373,7 @@ void Joiner::HandleJoinerEntrust(Coap::Header &aHeader, Message &aMessage, const
     ExtendedPanIdTlv extendedPanId;
     NetworkNameTlv networkName;
     ActiveTimestampTlv activeTimestamp;
+    NetworkKeySequenceTlv networkKeySeq;
 
     otLogFuncEntry();
 
@@ -398,7 +399,11 @@ void Joiner::HandleJoinerEntrust(Coap::Header &aHeader, Message &aMessage, const
     SuccessOrExit(error = Tlv::GetTlv(aMessage, Tlv::kActiveTimestamp, sizeof(activeTimestamp), activeTimestamp));
     VerifyOrExit(activeTimestamp.IsValid(), error = kThreadError_Parse);
 
+    SuccessOrExit(error = Tlv::GetTlv(aMessage, Tlv::kNetworkKeySequence, sizeof(networkKeySeq), networkKeySeq));
+    VerifyOrExit(networkKeySeq.IsValid(), error = kThreadError_Parse);
+
     mNetif.GetKeyManager().SetMasterKey(masterKey.GetNetworkMasterKey(), masterKey.GetLength());
+    mNetif.GetKeyManager().SetCurrentKeySequence(networkKeySeq.GetNetworkKeySequence());
     mNetif.GetMle().SetMeshLocalPrefix(meshLocalPrefix.GetMeshLocalPrefix());
     mNetif.GetMac().SetExtendedPanId(extendedPanId.GetExtendedPanId());
     mNetif.GetMac().SetNetworkName(networkName.GetNetworkName());
diff --git a/src/core/meshcop/joiner_router.cpp b/src/core/meshcop/joiner_router.cpp
index b4a3e7721..2bed446a8 100644
--- a/src/core/meshcop/joiner_router.cpp
+++ b/src/core/meshcop/joiner_router.cpp
@@ -318,6 +318,7 @@ ThreadError JoinerRouter::SendJoinerEntrust(const Ip6::MessageInfo &aMessageInfo
     MeshLocalPrefixTlv meshLocalPrefix;
     ExtendedPanIdTlv extendedPanId;
     NetworkNameTlv networkName;
+    NetworkKeySequenceTlv networkKeySequence;
     Tlv *tlv;
 
     otLogFuncEntry();
@@ -389,6 +390,10 @@ ThreadError JoinerRouter::SendJoinerEntrust(const Ip6::MessageInfo &aMessageInfo
         SuccessOrExit(error = message->Append(&securityPolicy, sizeof(securityPolicy)));
     }
 
+    networkKeySequence.Init();
+    networkKeySequence.SetNetworkKeySequence(mNetif.GetKeyManager().GetCurrentKeySequence());
+    SuccessOrExit(error = message->Append(&networkKeySequence, networkKeySequence.GetSize()));
+
     messageInfo = aMessageInfo;
     messageInfo.SetPeerPort(kCoapUdpPort);
     SuccessOrExit(error = mCoapClient.SendMessage(*message, messageInfo));
diff --git a/src/core/meshcop/tlvs.hpp b/src/core/meshcop/tlvs.hpp
index 50f24fbe0..254bd3eb9 100644
--- a/src/core/meshcop/tlvs.hpp
+++ b/src/core/meshcop/tlvs.hpp
@@ -69,6 +69,7 @@ public:
         kNetworkName             = OT_MESHCOP_TLV_NETWORKNAME,               ///< Newtork Name TLV
         kPSKc                    = OT_MESHCOP_TLV_PSKC,                      ///< PSKc TLV
         kNetworkMasterKey        = OT_MESHCOP_TLV_MASTERKEY,                 ///< Network Master Key TLV
+        kNetworkKeySequence      = OT_MESHCOP_TLV_NETWORK_KEY_SEQUENCE,      ///< Network Key Sequence TLV
         kMeshLocalPrefix         = OT_MESHCOP_TLV_MESHLOCALPREFIX,           ///< Mesh Local Prefix TLV
         kSteeringData            = OT_MESHCOP_TLV_STEERING_DATA,             ///< Steering Data TLV
         kBorderAgentLocator      = OT_MESHCOP_TLV_BORDER_AGENT_RLOC,         ///< Border Agent Locator TLV
@@ -449,6 +450,49 @@ private:
     uint8_t mNetworkMasterKey[16];
 } OT_TOOL_PACKED_END;
 
+/**
+ * This class implements Network Key Sequence TLV generation and parsing.
+ *
+ */
+OT_TOOL_PACKED_BEGIN
+class NetworkKeySequenceTlv: public Tlv
+{
+public:
+    /**
+     * This method initializes the TLV.
+     *
+     */
+    void Init(void) { SetType(kNetworkKeySequence); SetLength(sizeof(*this) - sizeof(Tlv)); }
+
+    /**
+     * This method indicates whether or not the TLV appears to be well-formed.
+     *
+     * @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(Tlv); }
+
+    /**
+     * This method returns the Network Key Sequence value.
+     *
+     * @returns The Network Key Sequence value.
+     *
+     */
+    uint32_t GetNetworkKeySequence(void) const { return HostSwap32(mNetworkKeySequence); }
+
+    /**
+     * This method sets the Network Key Sequence value.
+     *
+     * @param[in]  aNetworkKeySequence  The Network Key Sequence value.
+     *
+     */
+    void SetNetworkKeySequence(uint32_t aNetworkKeySequence) { mNetworkKeySequence = HostSwap32(aNetworkKeySequence); }
+
+private:
+    uint32_t mNetworkKeySequence;
+} OT_TOOL_PACKED_END;
+
 /**
  * This class implements Mesh Local Prefix TLV generation and parsing.
  *