This dress is so pretty, I rented it for our family cherry blossoms photo shoot and my daughter looked like a little cherry blossom. Really pretty, she loved it, and comfy, though the weather was a little colder than expected for this spring/summer dress. I got her the6, and she's 5 and a half, and on the slim side, and it seemed to work. The 5 may also have worked but this size was fine.

Rented two of these for my daughters for family pics - and 8 for the 8 year old (her normal size) and a 5 for the 5 year old (her normal size). The 5 year old ended up wearing the 8. These were SO TINY. I would say size up at least 2 sizes. Very well made and classic.