Weight regain following bariatric surgery is largely attributed to reduced adherence to postoperative diet recommendations. As time from surgery increases, patients can experience internal states that make adhering to these recommendations difficult (e.g., return of hunger and food cravings). Acceptance-based behavioral treatments (ABTs) provide patients with skills to increase engagement in value-directed behavior (e.g., healthy eating), despite negative internal states. We previously developed a 10-week remotely-delivered ABT (ABTi) and preliminary results indicated high acceptability and preliminary efficacy in a small open trial (n=16). The goal of the current study was to further evaluate the effectiveness of this intervention. We randomized 71 participants to receive ABTi or to a waitlist control (WLC) condition. Following the 10-week intervention, participants assigned to ABTi demonstrated significantly greater percent total body weight loss compared to WLC (loss of .8% ± 2.8% vs. gain of .3% ± 1.8%, t(69)=2.1, p = .03). However, the mean weight loss achieved did not reach current standards of clinical significance. When clinically significant weight loss was operationalized as at least 3%, a significantly greater percentage of participants who received ABTi met this criteria compared to WLC (24.3% vs. 2.9%, χ2(1)=6.7, p = .01). Encouragingly, participants in ABTi reported significantly greater reductions in average daily caloric intake (-602 kcal vs. +15 kcal, F(1)=5.4, p = .02) and maladaptive eating behaviors (including binge eating and grazing) compared to WLC. These data further support the potential utility of ABTi after bariatric surgery, though future research is needed to enhance its effects.