Online interventions promoted to enhance cognitive ability hold great appeal for their potential positive impact in social, employment, and educational domains. Cognitive training programs have, thus far, not been shown to influence performance on tests of general cognitive aptitude. Strengthening Mental Abilities with Relational Training (SMART) is an online program that claims to raise intelligence quotient (IQ). This systematic review and meta-analysis evaluates the effect of SMART on indices of cognitive aptitude and academic performance. The review protocol was registered at PROSPERO (CRD42019132404). A systematic literature search of bibliographic databases (ERIC, PsycINFO, PubMed, Applied Social Sciences Index and Abstracts, Scopus, Proquest Psychology) identified five studies (N = 195) that met the criterion for inclusion. The risk of bias was assessed using the Cochrane Collaboration Risk of Bias ‘RoB 2’ tool. Overall, there was a moderate impact of SMART on measures of nonverbal IQ (g = 0.57, 95% CI [0.24, 0.89]). There was insufficient evidence to determine the impact of SMART on any other domain. All studies included in the review were judged to be at a high risk of bias for their primary outcome. Despite the methodological limitations of published studies to date, these initial findings suggest that a large-scale study of SMART is warranted.