diff --git a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_connections.h b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_connections.h
index b039e29..183e98c 100644
--- a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_connections.h
+++ b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_connections.h
@@ -484,9 +484,9 @@ public:
 	// Almost all connections use this default lock.  (A few special cases use a different lock
 	// so that they are locked at the same time as other objects.)
 	ConnectionLock m_defaultLock;
-	void AssertLocksHeldByCurrentThread( const char *pszTag = nullptr ) const
+	void _AssertLocksHeldByCurrentThread( const char *pszFile, int line, const char *pszTag = nullptr ) const
 	{
-		SteamNetworkingGlobalLock::AssertHeldByCurrentThread( pszTag );
+		SteamNetworkingGlobalLock::_AssertHeldByCurrentThread( pszFile, line, pszTag );
 		m_pLock->AssertHeldByCurrentThread();
 	}
 
@@ -872,9 +872,9 @@ public:
 	inline const SteamNetworkingIdentity &IdentityRemote() const { return m_connection.m_identityRemote; }
 	inline const char *ConnectionDescription() const { return m_connection.GetDescription(); }
 
-	void AssertLocksHeldByCurrentThread( const char *pszTag = nullptr ) const
+	void _AssertLocksHeldByCurrentThread( const char *pszFile, int line, const char *pszTag = nullptr ) const
 	{
-		m_connection.AssertLocksHeldByCurrentThread( pszTag );
+		m_connection._AssertLocksHeldByCurrentThread( pszFile, line, pszTag );
 	}
 
 	// Useful so we can use ScheduledMethodThinkerLockable
diff --git a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_lowlevel.cpp b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_lowlevel.cpp
index 472cb30..228c6e5 100644
--- a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_lowlevel.cpp
+++ b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_lowlevel.cpp
@@ -338,7 +338,7 @@ void LockDebugInfo::AboutToUnlock()
 	AssertMsg( false, "Unlocked a lock '%s' that wasn't held?", m_pszName );
 }
 
-void LockDebugInfo::AssertHeldByCurrentThread( const char *pszTag ) const
+void LockDebugInfo::_AssertHeldByCurrentThread( const char *pszFile, int line, const char *pszTag ) const
 {
 	ThreadLockDebugInfo &t = GetThreadDebugInfo();
 	for ( int i = t.m_nHeldLocks-1 ; i >= 0 ; --i )
@@ -350,7 +350,7 @@ void LockDebugInfo::AssertHeldByCurrentThread( const char *pszTag ) const
 		}
 	}
 
-	AssertMsg( false, "Lock '%s' not held", m_pszName );
+	AssertMsg( false, "%s(%d): Lock '%s' not held", pszFile, line, m_pszName );
 }
 
 
@@ -381,14 +381,14 @@ void SteamNetworkingGlobalLock::SetLongLockWarningThresholdMS( const char *pszTa
 	}
 }
 
-void SteamNetworkingGlobalLock::AssertHeldByCurrentThread()
+void SteamNetworkingGlobalLock::_AssertHeldByCurrentThread( const char *pszFile, int line )
 {
-	s_mutexGlobalLock.AssertHeldByCurrentThread();
+	s_mutexGlobalLock._AssertHeldByCurrentThread( pszFile, line );
 }
 
-void SteamNetworkingGlobalLock::AssertHeldByCurrentThread( const char *pszTag )
+void SteamNetworkingGlobalLock::_AssertHeldByCurrentThread( const char *pszFile, int line, const char *pszTag )
 {
-	s_mutexGlobalLock.AssertHeldByCurrentThread();
+	s_mutexGlobalLock._AssertHeldByCurrentThread( pszFile, line );
 	AddThreadLockTag( pszTag );
 }
 
diff --git a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_lowlevel.h b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_lowlevel.h
index d11a8cf..04f092b 100644
--- a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_lowlevel.h
+++ b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_lowlevel.h
@@ -378,7 +378,7 @@ struct LockDebugInfo
 	const char *const m_pszName;
 	const int m_nFlags;
 
-	void AssertHeldByCurrentThread( const char *pszTag = nullptr ) const;
+	void _AssertHeldByCurrentThread( const char *pszFile, int line, const char *pszTag = nullptr ) const;
 
 protected:
 	LockDebugInfo( const char *pszName, int nFlags ) : m_pszName( pszName ), m_nFlags( nFlags ) {}
@@ -457,6 +457,14 @@ struct ShortDurationLock : Lock<ShortDurationMutexImpl>
 };
 using ShortDurationScopeLock = ScopeLock<ShortDurationLock>;
 
+#ifdef DBGFLAG_ASSERT
+	#define AssertHeldByCurrentThread( ... ) _AssertHeldByCurrentThread( __FILE__, __LINE__ ,## __VA_ARGS__ )
+	#define AssertLocksHeldByCurrentThread( ... ) _AssertLocksHeldByCurrentThread( __FILE__, __LINE__,## __VA_ARGS__ )
+#else
+	#define AssertHeldByCurrentThread( ... ) _AssertHeldByCurrentThread( nullptr, 0,## __VA_ARGS__ )
+	#define AssertLocksHeldByCurrentThread( ... ) _AssertLocksHeldByCurrentThread( nullptr, 0,## __VA_ARGS__ )
+#endif
+
 /// Special utilities for acquiring the global lock
 struct SteamNetworkingGlobalLock
 {
@@ -465,8 +473,8 @@ struct SteamNetworkingGlobalLock
 	static void Lock( const char *pszTag );
 	static bool TryLock( const char *pszTag, int msTimeout );
 	static void Unlock();
-	static void AssertHeldByCurrentThread();
-	static void AssertHeldByCurrentThread( const char *pszTag );
+	static void _AssertHeldByCurrentThread( const char *pszFile, int line );
+	static void _AssertHeldByCurrentThread( const char *pszFile, int line, const char *pszTag );
 	static void SetLongLockWarningThresholdMS( const char *pszTag, int msWarningThreshold );
 };