Social support offers protection from depression and anxiety, possibly through its beneficial effects upon cognitive reappraisal. The present study evaluates potential mechanisms of social support, utilizing a reappraisal task in 121 undergraduates elevated on neuroticism. Participants were instructed to reinterpret stressful images with (Social Condition) and without (Solo Condition) the reminder of a social support figure. Aversiveness, negative affect, and positive affect ratings, as well as written reappraisal responses, were collected trial-by-trial. Results indicated that participants reported lower aversiveness and negative affect and higher positive affect when reinterpreting images in the Social Condition compared to the Solo Condition. Analyses of adherence ratings of written reappraisals revealed that participants generated reinterpretations more in the Social Condition than in the Solo Condition. Exploratory mediation analyses indicated that Condition was indirectly associated with reappraisal efficacy as measured by aversiveness and affect ratings through reappraisal adherence. Results suggest that cognitive reappraisal with the influence of social support may be more effective than cognitive reappraisal without such social influence, and thus may be a suitable target for interventions for depression and anxiety.