I wear an XL and ordered a 4x in 2 colors, blue and light green. The blue was true to size the green was much smaller, however, it still fit. Both were packaged in bags that had 4x listed on them but none of the gowns had any type of tags on themselves that would differentiate the sizing. That said, this is a perfect product! It is soft, light, it is a wonderful gown to wear on a summer night, I actually came back to order more but they were out of stock. Hopefully they will bring them back in stock.