Objectives: Animal hoarding is a special manifestation of hoarding disorder, characterized by the accumulation of animals and failure to provide them with minimal care. The main objective of this systematic review is to evaluate the characteristics of animal hoarding, focusing on the profile of affected individuals and the features of accumulation behavior. Methods: A systematic search of the literature was conducted in the electronic databases MEDLINE, Scopus, and LILACS until October 2022. We included case series (n ≥ 10) and cross-sectional studies assessing animal hoarding. Results: A total of 374 studies were initially retrieved. Most studies were classified as having poor quality and significant risk of bias. A total of 538 individuals with animal hoarding were evaluated. These individuals were predominantly middle-aged, unmarried women who lived alone in urban areas. Most of their residences had unsanitary conditions. Recidivism rates varied from 13-41%. Cats and dogs were the main hoarded species, mostly acquired through unplanned breeding, and disease, injury, behavioral problems, and a lack of hygiene were characreristic of their condition. Animal carcasses were found in up to 60% of the properties. Conclusion: Animal hoarding is a complex condition that requires urgent attention. More research is necessary to develop effective strategies that can save community resources, improve animal and human welfare, and prevent recidivism.