You may use SetWindowLong function with BS_MULTILINE parameter to set multi line caption of some button.
procedure TForm1.Button1Click(Sender: TObject); var TempButton: LongInt; begin TempButton:=GetWindowLong(Button1.Handle, GWL_STYLE); SetWindowLong(Button1.Handle, GWL_STYLE, TempButton or BS_MULTILINE); end;