This study examined how noun and verb processing in bilingual visual word recognition are affected by within and between-language overlap. We investigated how word class ambiguous noun and verb cognates are processed by bilinguals, to see if co-activation of overlapping word forms between languages benefits from additional overlap within a language, and whether this effect is sensitive to the grammatical category of a word. Although effects of form overlap are ubiquitous in studies on nouns, little is known about such effects in verbs. In two experiments, Dutch-English bilinguals performed lexical decision tasks in L2 in which cognate status and word class ambiguity were manipulated in nouns and verbs. Responses to verb targets in both experiments showed facilitatory effects of both types of overlap. In contrast, noun targets in both experiments showed only a cognate effect, but no ambiguity effect. We argue that the difference between verbs and nouns arises because verb representations are more complex than those of nouns. As a consequence, verb processing benefits more from within-language form overlap than noun processing.