Integrative psychotherapy is the integration of elements from different schools of psychotherapy in the treatment of a client. Integrative psychotherapy may also refer to the psychotherapeutic process of integrating the personality: uniting the "affective, cognitive, behavioral, and physiological systems within a person".

Initially, Sigmund Freud developed a talking cure called psychoanalysis; then he wrote about his therapy and popularized psychoanalysis. After Freud, many different disciplines splintered off. Some of the more common therapies include: psychodynamic psychotherapy, transactional analysis, cognitive behavioral therapy, gestalt therapy, body psychotherapy, family systems therapy, person-centered psychotherapy, and existential therapy. Hundreds of different theories of psychotherapy are practiced.

A new therapy is born in several stages. After being trained in an existing school of psychotherapy, the therapist begins to practice. Then, after follow up training in other schools, the therapist may combine the different theories as a basis of a new practice. Then, some practitioners write about their new approach and label this approach with a new name.

A pragmatic or a theoretical approach can be taken when fusing schools of psychotherapy. Pragmatic practitioners blend a few strands of theory from a few schools as well as various techniques; such practitioners are sometimes called eclectic psychotherapists and are primarily concerned with what works. Alternatively, other therapists consider themselves to be more theoretically grounded as they blend their theories; they are called integrative psychotherapists and are not only concerned with what works, but also why it works.

For example, an eclectic therapist might experience a change in their client after administering a particular technique and be satisfied with a positive result. In contrast, an integrative therapist is curious about the "why and how" of the change as well. A theoretical emphasis is important: for example, the client may only have been trying to please the therapist and was adapting to the therapist rather than becoming more fully empowered in themselves.

Recent developments in integrative psychotherapy highlight the use of structured treatment frameworks that organize therapy into phases, combining cognitive-behavioral, experiential, and relational strategies. These phased approaches aim to address enduring patterns rather than isolated symptoms, promoting continuity and measurable outcomes.

The most recent edition of the Handbook of Psychotherapy Integration (Norcross & Goldfried, 2005) recognized four general routes to integration: common factors, technical eclecticism, theoretical integration, and assimilative integration.

The first route to integration is called common factors and "seeks to determine the core ingredients that different therapies share in common". The advantage of a common factors approach is the emphasis on therapeutic actions that have been demonstrated to be effective. The disadvantage is that common factors may overlook specific techniques that have been developed within particular theories. Common factors have been described by Jerome Frank, Bruce Wampold, and Miller, Duncan and Hubble (2005). Common factors theory asserts it is precisely the factors common to the most psychotherapies that make any psychotherapy successful.