As the complexity, frequency, and severity of mental health disorders increases across the nation, Canadians are increasingly seeking out psychotherapeutic interventions. Equine assisted psychotherapy is one such intervention. Equine assisted psychotherapy is a collaborative, relationship-focused, intervention which concentrates on the client’s experiences within the human-equine relationship which forms within the therapeutic session with their clinical practitioner. To provide equine assisted psychotherapy, clinical practitioners must engage in continuing education to ensure their practice is safe, effective, and evidence informed. In this qualitative study, a constructivist grounded theory approach was used to generate a theory of equine assisted psychotherapy, Stable Foundations, and from it, explore the approaches through which clinical practitioners may learn equine assisted psychotherapy for the treatment of individuals affected by mental health disorders. Snowball and theoretical sampling were used to recruit 12 participants, nine of which were clinical practitioners utilizing equine assisted psychotherapy in their practice. Of these, five were also facilitators of continuing education into equine assisted psychotherapy. The additional three participants were equine professionals. All participants contributed through semi-structured interviews. Data collection and analysis was iterative. The core category emerging from the analysis and coding was Stable Foundation. It has six categories safety, consent, scope of practice, facilitated relationships, equine knowledge, and qualities of the clinical practitioners. In the construction of the theory, four categories emerged from the data speaking to the teaching and learning of clinical practitioners seeking to utilize equine assisted psychotherapy. These were continuing education, experiential learning, practice and application, and supervision and consultation. In developing a theory of equine assisted psychotherapy and speaking to the educational needs of clinical practitioners, equine assisted psychotherapy can be standardized for replication among interprofessional clinicians and potentially ensure that a minimum standard of learning is achieved. This will benefit the client who will receive a clinically appropriate and effective mental health intervention; clinicians will learn, practice, and supervise equine assisted psychotherapy using best practices; and horses participating in equine assisted psychotherapy will receive ethical and appropriate care.