Antineoplastic treatments can negatively affect body composition, leading to metabolic derangements and worse clinical outcomes in breast cancer patients. This scoping review assesses body adiposity changes during breast cancer therapy. We included clinical and observational studies, published until the last search date in any language, with women aged >18 years, after breast cancer diagnosis, at any clinical stage and with any history of breast cancer treatment, who had body adiposity quantified by imaging tools at least twice during follow-up. In total, 17 studies were included (n = 1,009 individuals), six of which found a significant increase in body adiposity during treatment, two found a significant decrease, one presented divergent findings according to the imaging method and the analyzed body adiposity depots, and eight studies found no significant change in the outcome. Selective estrogen receptor modulators were associated with increased body adiposity, whereas aromatase inhibitors were associated with its decrease (n = 3). Chemotherapy was associated with increased body adiposity (n = 1), and monoclonal antibody with reduced brown adipose tissue activity (n = 1). Breast cancer treatment may have different effects on body adiposity, according to its mechanisms and protocols. Further studies are necessary to better elucidate this scenario.