diff --git a/include/osgDB/ObjectWrapper b/include/osgDB/ObjectWrapper
index 8003cb8a3..80424880f 100644
--- a/include/osgDB/ObjectWrapper
+++ b/include/osgDB/ObjectWrapper
@@ -15,6 +15,7 @@
 #ifndef OSGDB_OBJECTWRAPPER
 #define OSGDB_OBJECTWRAPPER
 
+#include <OpenThreads/ReentrantMutex>
 #include <osgDB/Serializer>
 #include <osg/ScriptEngine>
 
@@ -169,6 +170,8 @@ protected:
     ObjectWrapperManager();
     virtual ~ObjectWrapperManager();
 
+    OpenThreads::ReentrantMutex _wrapperMutex;
+
     WrapperMap _wrappers;
     CompressorMap _compressors;
 
diff --git a/src/osgDB/ObjectWrapper.cpp b/src/osgDB/ObjectWrapper.cpp
index 1b98cedb0..07f5e0a20 100644
--- a/src/osgDB/ObjectWrapper.cpp
+++ b/src/osgDB/ObjectWrapper.cpp
@@ -647,6 +647,8 @@ void ObjectWrapperManager::addWrapper( ObjectWrapper* wrapper )
 {
     if ( !wrapper ) return;
 
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_wrapperMutex);
+
     WrapperMap::iterator itr = _wrappers.find( wrapper->getName() );
     if ( itr!=_wrappers.end() )
     {
@@ -660,12 +662,16 @@ void ObjectWrapperManager::removeWrapper( ObjectWrapper* wrapper )
 {
     if ( !wrapper ) return;
 
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_wrapperMutex);
+
     WrapperMap::iterator itr = _wrappers.find( wrapper->getName() );
     if ( itr!=_wrappers.end() ) _wrappers.erase( itr );
 }
 
 ObjectWrapper* ObjectWrapperManager::findWrapper( const std::string& name )
 {
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_wrapperMutex);
+
     WrapperMap::iterator itr = _wrappers.find( name );
     if ( itr!=_wrappers.end() ) return itr->second.get();
 
@@ -694,6 +700,8 @@ void ObjectWrapperManager::addCompressor( BaseCompressor* compressor )
 {
     if ( !compressor ) return;
 
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_wrapperMutex);
+
     CompressorMap::iterator itr = _compressors.find( compressor->getName() );
     if ( itr!=_compressors.end() )
     {
@@ -707,12 +715,16 @@ void ObjectWrapperManager::removeCompressor( BaseCompressor* compressor )
 {
     if ( !compressor ) return;
 
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_wrapperMutex);
+
     CompressorMap::iterator itr = _compressors.find( compressor->getName() );
     if ( itr!=_compressors.end() ) _compressors.erase( itr );
 }
 
 BaseCompressor* ObjectWrapperManager::findCompressor( const std::string& name )
 {
+    OpenThreads::ScopedLock<OpenThreads::ReentrantMutex> lock(_wrapperMutex);
+
     CompressorMap::iterator itr = _compressors.find( name );
     if ( itr!=_compressors.end() ) return itr->second.get();