Research is yet to consider the potential for personal trainers (PTs) to influence their client's thoughts and feelings surrounding their body. This pre-registered study explored a model of positive body image in women personal training clients in the UK. Participants (n = 234, mean age = 51) completed an online questionnaire assessing body mass index (BMI), perceived body acceptance by their PT and various other measures related to body image. Perceived body acceptance by the PT was indirectly, positively associated with client body appreciation through greater internal body orientation and negatively associated with client BMI. Findings suggest PTs may be an important source of body acceptance for their clients. Education of PTs should be considered for promoting positive body image in women fitness industry consumers.