ObjectiveSocial media are promising channels for health communication promoting positive weight‐related behaviors, but no prior studies have synthesized evidence on the independent effects of social media campaigns focused on promoting healthy eating, physical activity (PA), and healthy weight. This study aimed to fill that gap and inform future social media‐based obesity‐prevention research and practice by reviewing findings from studies testing the effects of such campaigns on individual‐level cognitive, behavioral, and anthropometric outcomes.MethodThe Web of Science and PubMed databases were searched for peer‐reviewed articles published between 2012 and 2023 that explored the independent effects of social media campaigns related to healthy eating, PA, or weight management. Study characteristics and outcomes were extracted and summarized.ResultsEleven studies were included in this review describing campaigns targeting healthy eating‐related outcomes (e.g., fruit and vegetable consumption, meal preparation, nutrition label reading), PA, or weight management. Most campaigns (n = 7) were developed by universities or research centers. Priority audiences included parents, adult females, adolescents, college students, and adult government employees. The majority (n = 8) of the campaigns used single platforms, with the most common being Facebook, Instagram, blogs, and YouTube. Campaigns had mixed effects on cognitive outcomes (e.g., intention, attitude, knowledge), behavioral outcomes (e.g., food choices, PA), and anthropometric outcomes (e.g., weight, waist circumference).ConclusionSocial media campaigns focused on promoting healthy eating, PA, and healthy weight had mixed effects on individual‐level cognitive, behavioral, and anthropometric outcomes. Various limitations of the included studies make it difficult to ascertain which factors influence campaign effectiveness. Advancing knowledge in this area is important, particularly given social media's widespread use and potential for broad reach. New research with features such as rigorous study designs, larger and more diverse samples, and strong theoretical foundations may provide important insights into what types of interventions are effective or not and under what conditions.