Bought this as an Easter dress for my almost 6 month old. Per the advice of the previous reviewers, I ordered up a size, 9-12mos. I went to a local photographer to have her picture taken in it a few days before Easter and we could not get the dang thing over her head!  I love Mud Pie clothing, but whoever designed this dress must not have much experience in dressing children as there was no zipper or button back, merely a narrow hole for the head. Keep in mind, I do not have a particularly large headed baby. I had to get it altered so that it would fit. It looked great, but I don't think it will fit for long and certainly not when she's 9-12 months. I suggest ordering up 2 sizes! Hope this helps!