Background: Postoperative outcomes vary considerably across bariatric patients and may be related to psychosocial factors. In this study, we examined whether a patients family support predicts weight loss and the remission of type 2 diabetes (T2DM) up to 5 years following surgery. Methods: Between 2008 to 2018, 359 patients completed a pre-surgical questionnaire before undergoing gastric bypass or sleeve gastrectomy. As part of the questionnaire, patients described their family support in terms of structure (marital status, number of family members in the household) and function (marriage satisfaction, family emotional support, family practical support). These were applied as predictors to percent total weight loss (%TWL) and T2DM remission at 1, 2, 3, 4, and 5 years following surgery. Results: Marital satisfaction was found to be a significant predictor of post-surgical weight trajectories. Namely, patients who reported higher marital satisfaction were more likely to sustain weight loss than patients who reported lower marital satisfaction. Conclusions: Given the link between marital support and long-term weight outcomes, providers could consider asking patients about their spousal relationships during pre-surgical counselling.