Social skills deficits and excesses are a defining aspect of mental retardation (MR). Research indicates that there is an established relationship between social skills and maladaptive behaviors. A number of studies demonstrate that the social competence of individuals with MR and comorbid psychopathology can be enhanced with social skills training. However, to design an effective training package, an accurate assessment of adaptive and social functioning must first be conducted. Unique problems arise when assessing social skills in individuals with severe and profound MR (i.e., individuals often have limited verbal repertoires). Thus, a clinician must often rely on observable behavior and caregiver report rather than self-report. The three most common methods for assessing social skills are behavioral observations, role-playing, and checklists. These assessment strategies will be discussed, as well as suggestions for future research.