Obesity occurs at 2-3 times the general population rate in persons living with a psychotic illness. The risk of obesity-related serious medical conditions like diabetes and heart disease are also two to three times higher in this population. Traditional behavioral weight management approaches help more than half of these individuals to lose weight, but a significant proportion are not helped. This pilot study is intended to determine the feasibility, efficacy, acceptability, and potential clinical utility of an intervention that integrates mindfulness, acceptance, distress tolerance, and motivation and commitment combined with traditional behavioral strategies for weight loss. This is the first study to investigate such an acceptance-based behavioral intervention for weight loss in psychotic illness. The results from this study will help to determine whether future research in this area is warranted with a larger sample, over a longer period of time.