It's for medium width. I'm finding though that the past year or two TB seems to be making their shoes narrower. I've held up the same styles in M width (Minnies in particular) for comparison and the newer ones indeed are cut more narrow. I assume it's a cost cutting measure. I have wide feet too, so not happy about this. I've switched (in ballet flats anyway) to Ferragamo My Joy style which seems to be more forgiving on width these days.