Behaviour therapy is based on the clinical application of learning theory principles. It consists of a large set of specific techniques and interventions rather than a unified theory. The selection of these techniques is guided by the client's symptoms and clinical diagnosis. For instance, treating phobias requires a different set of techniques than treating anger outbursts, and a depressed client is treated differently from an anxious one.

Behaviour therapies postulate that psychological distress arises due to faulty behaviour patterns or thought patterns. Therefore, the therapy focuses on the behaviour and thoughts of the client in the present. The past is relevant only to the extent of understanding the origins of these faulty patterns, not to be relived.

The foundation of behaviour therapy lies in formulating dysfunctional or faulty behaviours. The therapist identifies the factors which reinforce and maintain these behaviours and devises methods to change them.

Once the faulty behaviours causing distress are identified, a specific treatment package is chosen. The primary aim of this treatment is to extinguish or eliminate the faulty behaviours and substitute them with adaptive behaviour patterns.

To achieve this, the therapist uses antecedent operations and consequent operations. Antecedent operations control behaviour by changing something that precedes such a behaviour.