An open question in autism research is how to assess language abilities in this population. We investigated language development in monolingual and bilingual children with varying degrees of autism, ages 3 to 9, with the aim of better understanding vocabulary comprehension. Two different methodologies were used: the Receptive One-Word Picture Vocabulary Test (ROWPVT) and eye-tracker technique. We examined whether the eye-tracker could help in the assessment of these children because it does not require the child to point during the test. Four typically developing control children, 14 monolingual English children with moderate/mild autism, and 4 children (2 monolingual English, 2 bilingual Spanish/English) with severe autism were tested and the results of the ROWPVT test were compared to the eye-tracker results. Interestingly, bilingual children with severe autism had better results using eye-tracker than the traditional ROWPVT test. These results suggest that these children know more vocabulary than traditional test measures indicate.