Love these sandals for their comfort but, sadly, over the years their sizes have drifted. I'm a size 6.5 so the S is too small (my heels just barely reach off the end of the shoe) and the M is way too big (lots of extra toe room and too much in the back). Based on others' advice I tried the girls flirty braidy sandal instead in Large (4-5) and, while they have a little less arch support, are still super comfy and fit well. Plus they're $35 instead of $50, so a win!