People with Williams syndrome, a neurodevelopmental genetic syndrome, typically have good language skills as compared to other cognitive abilities, as far as intellectual disability is concerned. They have a large vocabulary and they frequently use uncommon or rarely-used words. This has led some authors to consider that they have a peculiar semantic system, different from that of people with typical development. In this study, we tested this hypothesis by comparing the performance of a group of young adults with Williams syndrome to a control group using various lexico-semantic tasks, including semantic and phonological fluency. The results indicate that the semantic system of people with Williams syndrome does not seem to differ much from those in the control group because the words they produced were similar to those of the control group with regard to word frequency, length or the typicality of the responses within the categories.