We investigate whether Italian native speakers and Italian children can order the quantifiers of their language on a magnitude scale. We look at three indefinite low-magnitude quantifiers (alcuni, pochi, qualche, ‘a few’) and three indefinite high-magnitude quantifiers (molti, parecchi, tanti, ‘many’). Dictionaries suggest that these quantifiers refer to different magnitudes, which would not only justify their co-existence in the language, but should also make scalar ordering possible. In two experiments, 96 adults and 16 five-year-old children took part in a magnitude comparison task. The results show a developmental difference in so-called “synonymous” quantifiers, which we explain by suggesting that children apply the Principle of Contrast to quantifiers.