This paper deals with ASL nouns and demonstrates (despite previous suggestions in the literature) that ASL belongs to Chierchia’s group (III), i.e. languages without overt number marking and a visible countability distinction. Although the countability distinction appears to be hidden at first glance, it can be flushed out. I account for the phenomenon in terms of properties of [n+__ ], showing that the countability distinction must be grammatical in ASL. This paper is thus a first step towards an examination of the count/mass distinction in ASL. We find that as predicted by the previous literature (Chierchia 2010, Deal 2017), the countability distinction in ASL, albeit not being immediately visible at all, is connected to number marking.