Given the research that suggests the social use of language is the latest developing aspect of language, it was hypothesized that children with speech/language impairment (SLI) are particularly susceptible to social interaction difficulties, resulting in diminished social competence. This hypothesis was explored with SLI and non-language-impaired (NLI) 4- and 5-year-old children by gathering measures of social problem solving ability (as rated by teachers, parents, and peers), emotion knowledge, and language development. Results provided partial support for the hypothesis above. Speech/language-impaired children were rated significantly lower on parent ratings of self-control and higher in internalizing behaviors, and lower on teacher ratings of assertiveness, than the NLI controls. There were no differences noted on peer sociometric ratings or mutual friendships. However, SLI children scored lower on a stereotypical test of emotional knowledge, while scoring similarly to NLI controls on a nonstereotypical test. A test of language development (TELD-2) differentiated the SLI and NLI groups, both expressively and receptively. In addition, the TELD-2 indicated a significant difference in semantic processing errors, but not syntax errors, between the two groups. The differential effects of speech/language impairment on the development of social competence were explored. (Contains 2 tables.)