diff --git a/rtl/objpas/classes/classes.inc b/rtl/objpas/classes/classes.inc
index ac59f61e5b..715de5b8f1 100644
--- a/rtl/objpas/classes/classes.inc
+++ b/rtl/objpas/classes/classes.inc
@@ -236,7 +236,7 @@ begin
 // enable for all platforms once http://bugs.freepascal.org/view.php?id=16884
 // is fixed for all platforms (in case the fix for non-unix platforms also
 // requires this field at least)
-{$if defined(unix) or defined(windows)}
+{$if defined(unix) or defined(windows) or defined(os2)}
   if not FExternalThread and not FInitialSuspended then
     Resume;
 {$endif}
diff --git a/rtl/objpas/classes/classesh.inc b/rtl/objpas/classes/classesh.inc
index adb906bca7..ca7a463b53 100644
--- a/rtl/objpas/classes/classesh.inc
+++ b/rtl/objpas/classes/classesh.inc
@@ -1602,7 +1602,7 @@ type
     procedure Queue(aMethod: TThreadMethod);
     property ReturnValue: Integer read FReturnValue write FReturnValue;
     property Terminated: Boolean read FTerminated;
-{$ifdef windows}
+{$if defined(windows) or defined(OS2)}
   private
     FInitialSuspended: boolean;
 {$endif}
diff --git a/rtl/os2/tthread.inc b/rtl/os2/tthread.inc
index ece7c3dc49..28a4922942 100644
--- a/rtl/os2/tthread.inc
+++ b/rtl/os2/tthread.inc
@@ -107,8 +107,11 @@ var
   Flags: cardinal;
 begin
   AddThread;
-  Flags := dtStack_Commited;
+  { Always start in suspended state, will be resumed in AfterConstruction if necessary
+    See Mantis #16884 }
+  Flags := dtStack_Commited or dtSuspended;
   FSuspended := CreateSuspended;
+  FInitialSuspended := CreateSuspended;
   if FSuspended then Flags := Flags or dtSuspended;
   FHandle := BeginThread (nil, StackSize, @ThreadProc, pointer (Self),
                                                              Flags, FThreadID);