Animal-assisted therapy is a practical example of the One Health approach, integrating human, animal, and environmental health. Our research group has studied the effects of dog-assisted therapy (DAT) on institutionalized elderly people with dementia, where significant improvements were observed in emotional, social, and behavioral well-being, a reduction in agitation and problematic behaviors, and less functional and cognitive decline compared to the control group. More recently, with horses and children with ASD, equine-assisted sessions favored communication, social interaction, adaptive behavior, and daily life skills. The One Health perspective is reflected in the design of the programs: animals receive specialized training, supervision, and care, while intervention environments are adapted to ensure safety and comfort for both humans and animals. This allows for shared well-being and promotes environmental quality. Existing evidence suggests these interventions are safe and effective, but emphasizes the need for additional multicenter studies, long term follow-up, and objective multidimensional measures to consolidate them as an integrated intervention model that generates shared benefits. All of this encourages us to continue this line of research, expanding to new sociosanitary contexts, animals, and groups to improve everyone’s quality of life.