We demonstrate a U-shaped developmental trajectory in the interpretation of scopally ambiguous sentences, with 4-year-olds and adults, but not 5-year-olds, accessing inverse scope. These results argue against any view that treats 5-year-olds failures as resulting from immaturity of a single mechanism. Instead, we propose that this developmental pattern derives from the development of (a) parsing mechanisms that generate multiple interpretations in addition to (b) processes involved in selecting or revising among these. (Contains 2 figures, 1 table and 5 footnotes.)