Simple SummaryComplementary and alternative veterinary medicine (CAVM) is commonly used in animals. However, there is limited knowledge of how the methods affect the animal. Therefore, this study reviews the scientific literature of 24 different CAVM therapies used in cats, dogs, and horses. Three core bibliographic sources were used. Relevant articles were assessed for scientific quality, and information was extracted on study characteristics, species, type of treatment, indication, and treatment effects. Of 982 unique publications screened, 42 were eligible for inclusion, representing nine different CAVM therapies, which were aromatherapy, gold therapy, homeopathy, leeches (hirudotherapy), mesotherapy, mud, neural therapy, sound (music) therapy, and vibration therapy. For the other 15 predefined therapies, no study was identified. The risk of bias was assessed as high in 17 studies, moderate to high in 10, moderate in 10, low to moderate in four, and low in one study. In those studies where the risk of bias was low to moderate, there was considerable heterogeneity in reported treatment effects. Therefore, the 24 CAVM therapies do not have scientific documentation of sufficient quality to draw clear conclusions regarding their clinical effect. There is an increasing interest in complementary and alternative veterinary medicine (CAVM). There is, however, an uncertainty of the efficacy of these methods. Therefore, the aim of this systematic literature review is to assess the evidence for clinical efficacy of 24 CAVM therapies used in cats, dogs, and horses. A bibliographic search, restricted to studies in cats, dogs, and horses, was performed on Web of Science Core Collection, CABI, and PubMed. Relevant articles were assessed for scientific quality, and information was extracted on study characteristics, species, type of treatment, indication, and treatment effects. Of 982 unique publications screened, 42 were eligible for inclusion, representing nine different CAVM therapies, which were aromatherapy, gold therapy, homeopathy, leeches (hirudotherapy), mesotherapy, mud, neural therapy, sound (music) therapy, and vibration therapy. For 15 predefined therapies, no study was identified. The risk of bias was assessed as high in 17 studies, moderate to high in 10, moderate in 10, low to moderate in four, and low in one study. In those studies where the risk of bias was low to moderate, there was considerable heterogeneity in reported treatment effects. Therefore, the scientific evidence is not strong enough to define the clinical efficacy of the 24 CAVM therapies.