The Role of Therapist Attachment in Alliance and Outcome: A Systematic Literature Review Amy Degnan, 1 Annily Seymour-Hyde, 1 Alison Harris 2 and Katherine Berry 1 * 1 School of Psychological Sciences, University of Manchester, Manchester, UK 2 Greater Manchester West Mental Health Foundation Trust, Prestwich, UK Objectives: This review examined the impact of therapist attachment style on therapeutic alliance and outcomes. Methods: Systematic search procedures yielded 11 studies for inclusion that measured associations be- tween therapist attachment style and alliance and/or outcome. Results: There is some preliminary evidence that therapist attachment style and interactions between therapist and client attachment style contribute to alliance and therapy outcomes. However, methodo- logical weaknesses and heterogeneity across studies highlight the need for more rigorously designed research in this area. Conclusions: There is sufficient evidence to suggest that therapists need to pay attention to the influ- ence of their own attachment style in therapeutic processes and that there is merit in pursing this area of research further. The review is important in highlighting key design issues to consider in future stud- ies. Copyright © 2014 John Wiley & Sons, Ltd. Key Practitioner Message: • Therapist attachment style has the potential to influence therapeutic alliance and client outcome. • Improvements in therapeutic practice might be achieved if therapists have greater knowledge of their own attachment styles and how these interact with their clients’ attachment styles to influence the psy- chotherapy relationship and outcomes. • From the outset of their careers, therapists should receive training and supervision to enhance the awareness of their individual attachment experiences and how these play out during the therapeutic process. Keywords: Attachment, Alliance, Therapy Outcome, Therapist Bordin (1994) outlines three components that constitute the quality of the therapeutic alliance: (a) therapist and cli- ent agreement on the goals of therapy; (b) therapist and client agreement on the tasks of therapy; and (c) emotional bond between the therapist and client. Meta-analytic stud- ies show that the working alliance is an important predic- tor of outcome, with alliance–outcome effect size estimates typically reported in the range of 0.22–0.26 (Horvath, Del Re, Flückiger, & Symonds, 2011; Martin, Garske, & Davis, 2000). Given the importance of the working alliance to thera- peutic outcomes, research has focused on identifying key factors that improve or weaken the alliance during ther- apy. Evidence suggests that characteristics of both clients and therapists influence the development of the alliance (Norcross, 2011). However, research has traditionally placed greater focus on client characteristics. Bowlby’s (1988) attachment theory offers a useful frame- work within which to explore the therapeutic alliance. At- tachment is defined as a persistent affectional bond an individual forms with a significant other. Bowlby asserted that the attachment figure provides a ‘secure base’ with which the individual can explore the world and is used as a ‘safe haven’ during times of distress. Bowlby pro- posed that, as a result of interactions with caregivers during infancy and childhood, individuals develop affect-laden mental representations of the self in relation to significant others and expectations about how others behave in social relationships. From observational studies of infant–mother interac- tions, Ainsworth, Blehar, Waters and Wall (1978) identi- fied three different attachment patterns (secure, insecure avoidant and insecure anxious-ambivalent) that relate to different internal working models and methods of regulat- ing distress. If the infant receives sensitive caregiving that is responsive to his or her needs, a secure attachment style develops. This is associated with a positive image of the self and others, adaptive strategies for coping with dis- tress, behaving autonomously and the ability to develop *Correspondence to: Dr Katherine Berry, School of Psychological Sci- ences, The University of Manchester, 2nd Floor Zochonis Building, Brunswick Street, Manchester, M13 9PL, UK. E-mail: katherinelberry@yahoo.co.uk Clinical Psychology and Psychotherapy Clin. Psychol. Psychother. 23, 47–65 (2016) Published online 2 December 2014 in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/cpp.1937 Copyright © 2014 John Wiley & Sons, Ltd.