diff --git a/assignment-client/src/avatars/AvatarMixer.cpp b/assignment-client/src/avatars/AvatarMixer.cpp
index b9bc87ecf2..aaf58a7f42 100644
--- a/assignment-client/src/avatars/AvatarMixer.cpp
+++ b/assignment-client/src/avatars/AvatarMixer.cpp
@@ -114,21 +114,25 @@ void AvatarMixer::broadcastAvatarData() {
     
     NodeList* nodeList = NodeList::getInstance();
     
+    AvatarMixerClientData* nodeData = NULL;
+    AvatarMixerClientData* otherNodeData = NULL;
+    
     foreach (const SharedNodePointer& node, nodeList->getNodeHash()) {
-        if (node->getLinkedData() && node->getType() == NodeType::Agent && node->getActiveSocket()) {
+        if (node->getLinkedData() && node->getType() == NodeType::Agent && node->getActiveSocket()
+            && (nodeData = reinterpret_cast<AvatarMixerClientData*>(node->getLinkedData()))->getMutex().tryLock()) {
             ++_sumListeners;
             
             // reset packet pointers for this node
             mixedAvatarByteArray.resize(numPacketHeaderBytes);
             
-            AvatarMixerClientData* myData = reinterpret_cast<AvatarMixerClientData*>(node->getLinkedData());
-            AvatarData& avatar = myData->getAvatar();
+            AvatarData& avatar = nodeData->getAvatar();
             glm::vec3 myPosition = avatar.getPosition();
             
             // this is an AGENT we have received head data from
             // send back a packet with other active node data to this node
             foreach (const SharedNodePointer& otherNode, nodeList->getNodeHash()) {
-                if (otherNode->getLinkedData() && otherNode->getUUID() != node->getUUID()) {
+                if (otherNode->getLinkedData() && otherNode->getUUID() != node->getUUID()
+                    && (otherNodeData = reinterpret_cast<AvatarMixerClientData*>(otherNode->getLinkedData()))->getMutex().tryLock()) {
                     
                     AvatarMixerClientData* otherNodeData = reinterpret_cast<AvatarMixerClientData*>(otherNode->getLinkedData());
                     AvatarData& otherAvatar = otherNodeData->getAvatar();
@@ -158,7 +162,7 @@ void AvatarMixer::broadcastAvatarData() {
                         
                         // if the receiving avatar has just connected make sure we send out the mesh and billboard
                         // for this avatar (assuming they exist)
-                        bool forceSend = !myData->checkAndSetHasReceivedFirstPackets();
+                        bool forceSend = !nodeData->checkAndSetHasReceivedFirstPackets();
                         
                         // we will also force a send of billboard or identity packet
                         // if either has changed in the last frame
@@ -191,10 +195,14 @@ void AvatarMixer::broadcastAvatarData() {
                             ++_sumIdentityPackets;
                         }
                     }
+                
+                    otherNodeData->getMutex().unlock();
                 }
             }
             
             nodeList->writeDatagram(mixedAvatarByteArray, node);
+            
+            nodeData->getMutex().unlock();
         }
     }
     
@@ -238,6 +246,7 @@ void AvatarMixer::readPendingDatagrams() {
                         
                         // parse the identity packet and update the change timestamp if appropriate
                         if (avatar.hasIdentityChangedAfterParsing(receivedPacket)) {
+                            QMutexLocker nodeDataLocker(&nodeData->getMutex());
                             nodeData->setIdentityChangeTimestamp(QDateTime::currentMSecsSinceEpoch());
                         }
                     }
@@ -254,6 +263,7 @@ void AvatarMixer::readPendingDatagrams() {
                         
                         // parse the billboard packet and update the change timestamp if appropriate
                         if (avatar.hasBillboardChangedAfterParsing(receivedPacket)) {
+                            QMutexLocker nodeDataLocker(&nodeData->getMutex());
                             nodeData->setBillboardChangeTimestamp(QDateTime::currentMSecsSinceEpoch());
                         }
                         
diff --git a/assignment-client/src/avatars/AvatarMixerClientData.h b/assignment-client/src/avatars/AvatarMixerClientData.h
index bc0a54f06b..22ef69aa6e 100644
--- a/assignment-client/src/avatars/AvatarMixerClientData.h
+++ b/assignment-client/src/avatars/AvatarMixerClientData.h
@@ -9,6 +9,7 @@
 #ifndef __hifi__AvatarMixerClientData__
 #define __hifi__AvatarMixerClientData__
 
+#include <QtCore/QMutex>
 #include <QtCore/QUrl>
 
 #include <AvatarData.h>
diff --git a/libraries/shared/src/NodeData.cpp b/libraries/shared/src/NodeData.cpp
index a7fa18f409..e3800f8b93 100644
--- a/libraries/shared/src/NodeData.cpp
+++ b/libraries/shared/src/NodeData.cpp
@@ -8,6 +8,12 @@
 
 #include "NodeData.h"
 
+NodeData::NodeData() :
+    _mutex()
+{
+    
+}
+
 NodeData::~NodeData() {
     
 }
\ No newline at end of file
diff --git a/libraries/shared/src/NodeData.h b/libraries/shared/src/NodeData.h
index cf800fc3cd..99b5fda9be 100644
--- a/libraries/shared/src/NodeData.h
+++ b/libraries/shared/src/NodeData.h
@@ -16,9 +16,14 @@ class Node;
 class NodeData : public QObject {
     Q_OBJECT
 public:
-    
+    NodeData();
     virtual ~NodeData() = 0;
     virtual int parseData(const QByteArray& packet) = 0;
+    
+    QMutex& getMutex() { return _mutex; }
+
+private:
+    QMutex _mutex;
 };
 
 #endif
diff --git a/libraries/shared/src/NodeList.cpp b/libraries/shared/src/NodeList.cpp
index 85e981490e..e80f25709a 100644
--- a/libraries/shared/src/NodeList.cpp
+++ b/libraries/shared/src/NodeList.cpp
@@ -317,6 +317,8 @@ int NodeList::updateNodeWithDataFromPacket(const SharedNodePointer& matchingNode
         linkedDataCreateCallback(matchingNode.data());
     }
     
+    QMutexLocker linkedDataLocker(&matchingNode->getLinkedData()->getMutex());
+    
     return matchingNode->getLinkedData()->parseData(packet);
 }