There is debate regarding the relationship between autism and specific language impairment (SLI), with some researchers proposing aetiological overlap between the conditions and others maintaining their aetiological distinction. Although considerable research has investigated the language phenotypes of these disorders, the relationship between the cognitive phenotypes has been left relatively unexplored. This paper reviews relevant literature on whether individuals with SLI exhibit cognitive characteristics reminiscent of autism. Overall, findings are inconsistent and there is a lack of substantive evidence supporting overlapping cognitive phenotypes in autism and SLI. Better powered and more rigorous experimental designs, as well as studies directly comparing the cognitive phenotype of children with SLI and those with autism will further elucidate the aetiological relationship between these two conditions.