Acceptance and commitment therapy (ACT, typically pronounced as the word “act”) is a form of psychotherapy commonly described as a form of cognitive-behavior therapy or of clinical behavior analysis (CBA). It is an empirically-based psychological intervention that uses acceptance and mindfulness strategies mixed in different ways with commitment and behavior-change strategies, to increase psychological flexibility. The approach was originally called comprehensive distancing. It was begun in 1982 by Steven C. Hayes and was first tested by Robert Zettle in 1985, but was built out into its modern form in the late 1980s.There are a variety of protocols for ACT, depending on the target behavior or setting. For example, in behavioral health areas a brief version of ACT is called focused acceptance and commitment therapy (FACT).

The objective of ACT is not elimination of difficult feelings; rather, it is to be present with what life brings us and to “move toward valued behavior”. Acceptance and commitment therapy invited people to open up to unpleasant feelings, and learn not to overreact to them, and not avoiding situations where they are invoked. Its therapeutic effect is a positive spiral where feeling better leads to a better understanding of the truth.