This study investigated the effects of experiences with weight stigma and weight bias internalization on exercise. An online sample of 177 women with overweight and obesity (M _age = 35.48 years, M _BMI = 32.81) completed questionnaires assessing exercise behavior, self-efficacy, and motivation; experiences of weight stigmatization; weight bias internalization; and weight-stigmatizing attitudes toward others. Weight stigma experiences positively correlated with exercise behavior, but weight bias internalization was negatively associated with all exercise variables. Weight bias internalization was a partial mediator between weight stigma experiences and exercise behavior. The distinct effects of experiencing versus internalizing weight bias carry implications for clinical practice and public health.