Treatment manuals for the conduct of psychotherapy vary in recommendations for appropriate therapist attire. Moreover, these recommendations are often not based on research evidence, and what research exists is contradictory in terms of what types of clothing might result in the best perception of the therapist. Some past research has found higher ratings of therapists wearing informal attire, others have observed higher ratings with formal attire, and some have found no difference. The aim of this experimental study is to provide further evidence concerning the potential role of therapist attire on client perceptions of the therapist. In the study, participants will be randomly assigned to view videos of therapy interactions in which the therapists wear either formal or informal attire. Participants will then complete ratings of the therapist in terms of perceived therapist credibility, therapist empathy, and the therapeutic alliance. Data will be analyzed using a repeated-measures analysis of variance. The analysis of data will allow an evaluation of possible differing perceptions of a therapist depending on attire. If a difference is observed, the results could have implications for training recommendations of dress standards for mental health practitioners.