A greater understanding of the links between cognitive and social functioning changes is needed to refine cognitive treatments for schizophrenia. To date, studies have been cross-sectional, and few have investigated the impact of cognitive change. This single-blind randomized controlled trial explored the links between changes in executive/memory functions and social behavior, as well as the moderating effect of cognitive remediation therapy (CRT). A total of 85 participants with schizophrenia received 40 sessions of CRT (an individual psychological therapy aiming to improve attention, memory, and problem solving) or treatment-as-usual. At baseline, social functioning was significantly associated with "verbal working memory," "response inhibition," "verbal long-term memory," and "visuo-spatial long-term memory," but not "schema generation," factors. However, only improvement in "schema generation" predicted improved social functioning. This was true whether or not participants had received CRT. These results suggest that cross-sectional associations between cognitive functions and social functioning may not offer the best means for identifying good targets for intervention. Improvement in the ability to generate new schemas has a beneficial impact on social functioning.