Breast animation deformity (BAD) has been reported to occur after submuscular implant placement following breast augmentation and immediate breast reconstruction. Despite its apparent impact on patients’ quality of life, BAD has only recently become a topic of general concern. Its incidence and etiology have yet to be established. The aim of this systematic review was to identify papers that clearly defined and classified BAD and described how the degree of animation was assessed. We performed a search in PubMed and Embase. Studies meeting the inclusion criteria that described BAD after implant-based breast augmentation or immediate breast reconstruction were included. After screening 866 publications, four studies were included: three describing BAD after breast augmentation and one describing BAD after immediate breast reconstruction. The median percentage of patients with some degree of BAD was 58%. The highest percentages were found in patients operated on using the Regnault technique or the dual-plane technique (73%–78%). The lowest percentages were found following the dual-plane muscle-splitting technique (30%) and the triple-plane technique (33%). We found no studies meeting the inclusion criteria that analyzed BAD after prepectoral implant placement. This review of the current literature suggests that the degree of BAD is proportional to the degree of muscle involvement. Evidence is scarce, and the phenomenon seems to be underreported. Future comparative studies are warranted.