So which button are you stupposed to button on a 3-button suit jacket? Top or middle? Thanks If the lapel is rolled so as the top button-hole is in the curve of the lapel, then it is not meant to be buttoned. That is the traditional three button suit. If the lapels of the jacket are pressed so the lapel ends before the top button-hole, then the top and middle are to be buttoned. I have never liked that look, and I think it looks contrived and too trendy. I never abandoned the two button suit. Three years ago I passed up a great deal on a Norman Hilton three-button, because the "sack" styling lacks a suppressed waist. It makes everyone look dumpy. The definitive answer on which button to fasten for any suit jacket is always and only the top button. If there are three buttons, then that is one too many.