I bought this dress the 1st time in my size (1X) & it fit like a pillow case, but it is meant to be oversized. I went all the way down to a size small (i like a tight fit) & it fits perfectly. I still have room in the dress, as it's very stretchy, breathable fabric. The dress is oversized, so if you want oversized, i still suggest going down 1 size so it doesn't fit like a bedsheet, but if you want a tighter fit, I recommend going down several sizes. the fabric is thin-medium, it doesn't give you that "it'll tear in the washer" thin, but it's not heavy either. It's one of my favorite daytime dresses.