I ordered a S/M. I'm 5'3 and am a 0-1 for shorts and dresses. The romper fits perfect, I'm in love with it. And wear it all the time. I ordered 6 things and this came the fastest. It looks as cute on as it does on the model.
This romper is awesome! I got a size medium and normally get a small. The bottom part fits perfectly and covers my whole butt, but the top is slightly to big but a few safety pins fixed this! The material is very thin but soft. I would definitely recommend getting yourself one!