Analogy is broadly described as relating two situations that share a common pattern of relations among their constituent elements (e.g., Holyoak, 2005), whereas most theorists consider the metaphor as a special type of analogy in which one of the situations is more representative than the other (e.g., Gentner, Bowdle, Wolff, & Boronat, 2011). Both analogy and metaphor facilitate the rapid understanding of one situation by reference to another. This generative ability has turned them into very frequently used tools in diverse applied settings (Bassok & Holyoak, 1989; Blanchette & Dunbar, 2001; Capelli & Jolibert, 2009; Hesse, 1966). For instance, multiple forms of psychotherapy have emphasized the use of metaphor as a way to facilitate the clients' understanding of their problems and experiences by reference to another situation that is clearer and more representative (e.g., Kopp, 1995; Stoddard & Afari, 2014; Tay, 2013; Tomeke, 2016). This emphasis of psychotherapy on metaphor is not surprising because it usually addresses abstract topics (e.g., emotions, feelings, expectations) that have their own origin in metaphor (e.g., Lakoff & Johnson, 1981; Skinner, 1945). Furthermore, psychotherapy usually addresses counterintuitive facts that are more difficult to understand when referring to them directly (e.g., Tomeke, 2016; Villatte, Villatte, & Hayes, 2016).In spite of its recognized relevance for psychotherapy, relatively little research has been conducted to isolate the specific components that make metaphors more useful in this setting. McCurry and Hayes (1992) conducted a review of the field, finding that three components seem to be associated with the successful use of metaphors: memorability, comprehensibility, and aptness. However, the specific factors that promote these components are not very well known. Subsequent research has found that the number of metaphors used in therapy is not an important factor but instead the cooperation between the therapist and the client in the generation of metaphors (Angus, 1996; Angus & Rennie, 1988; Torneke, 2016). Additional research has found that the use of metaphor by the therapist increases the chances that the client will remember the session (Martin, Cummings, & Hallberg, 1992).Two main problems have been detected in metaphor research in psychotherapy (e.g., McMullen, 2008; Tay, 2013; Torneke, 2016). On the one hand, studies on the topic often use different definitions of metaphor, which hinders the communication and replication of results. On the other hand, the research conducted has analyzed metaphor independently of the context in which it is used. Therefore, a more functional approach to metaphor use in psychotherapy is needed in which the research question would be what features of metaphor facilitate the accomplishment of specific therapeutic goals (McMullen, 2008; Tomeke, 2016). This research rationale would lead to the analysis of metaphor as used in different forms of psychotherapy to obtain specific objectives.Acceptance and commitment therapy (ACT; Hayes, Strosahl, & Wilson, 1999) is usually recognized for the wide use of metaphors (e.g., Stoddard & Afari, 2014). ACT is a contextual-behavioral model of psychological intervention that pursues the promotion of psychological flexibility. As it is rooted in an approach of human language and cognition known as relational frame theory (RFT; Hayes, Barnes-Holmes, & Roche, 2001), ACT is in a priviledged position to develop a research program of metaphor that could potentially increase its efficacy. Precisely, one of the topics with more fruitful research within RFT is analogical reasoning (e.g., Ruiz & Luciano, 2012).RFT defines analogy as the establishment of a relation of coordination (i.e., sameness or equivalence) among common types of relations (Lipkens, 1992; Stewart, Bames-Holmes, Hayes, & Lipkens, 2001). For instance, if we establish relations of coordination between the Spanish words silla and estrella and the English words chair and star, then we could establish a simple analogy by deriving a frame of coordination between the two trained relations (i. …