Background: Obesity and comorbid conditions are associated with worse outcomes related to COVID-19. Moreover, social distancing adherence during the COVID-19 pandemic may predict weight gain due to decreased physical activity, increased emotional eating, and social isolation. While early studies suggest that many individuals struggled with weight management during the pandemic, less is known about healthy eating and weight control behaviors among those enrolled in weight loss programs. Methods: The present study evaluated weight management efforts among weight loss program participants during the COVID-19 pandemic. Participants’ (N = 55, 90.9% female, 36% white, Mage = 49.8) demographics and body mass index were collected two months prior to the COVID-19 statewide shutdown. During the lockdown, an online survey assessed health behaviors, coping, COVID-19 experiences (e.g., social distancing, loneliness), and weight gain. Logistic regressions examined demographics, health behaviors, and COVID-19 factors as predictors of weight gain. Results: Most participants (58%) reported gaining weight during COVID-19. Weight gain was predicted by challenges with the following health behaviors: physical activity, monitoring food intake, choosing healthy foods, and emotional eating. Loneliness and working remotely significantly related to emotional eating, physical activity, and choosing healthy foods. Conclusions: Loneliness and working remotely increased the difficulty of weight management behaviors during COVID-19 among weight loss program participants. However, staying active, planning and tracking food consumption, choosing healthy foods, and reducing emotional eating protected against weight gain. Thus, these factors may be key areas for weight management efforts during the pandemic.