diff --git a/rtl/unix/cthreads.pp b/rtl/unix/cthreads.pp
index 92aae01824..08e52dbcb6 100644
--- a/rtl/unix/cthreads.pp
+++ b/rtl/unix/cthreads.pp
@@ -494,6 +494,8 @@ Type  PINTRTLEvent = ^TINTRTLEvent;
 {$endif}
     begin
 {$if defined(Linux) or defined(Android)}
+      if ThreadName = '' then
+        Exit;
   {$ifdef dynpthreads}
       if Assigned(pthread_setname_np) then
   {$endif dynpthreads}
diff --git a/rtl/win/systhrd.inc b/rtl/win/systhrd.inc
index 6ba68d421a..10bb07fda4 100644
--- a/rtl/win/systhrd.inc
+++ b/rtl/win/systhrd.inc
@@ -400,6 +400,9 @@ var
     procedure SysSetThreadDebugNameA(threadHandle: TThreadID; const ThreadName: AnsiString);
     begin
 {$ifndef WINCE}
+      if ThreadName = '' then
+        Exit;
+
       if WinIsDebuggerPresent then
       begin
         RaiseMSVCExceptionMethod(threadHandle, ThreadName);
@@ -417,6 +420,9 @@ var
     procedure SysSetThreadDebugNameU(threadHandle: TThreadID; const ThreadName: UnicodeString);
     begin
 {$ifndef WINCE}
+      if ThreadName = '' then
+        Exit;
+
       if WinIsDebuggerPresent then
       begin
         RaiseMSVCExceptionMethod(threadHandle, AnsiString(ThreadName));