Virtual reality (VR) has been shown to be eff ective in the treatment of anxiety disorders. The eff ects of a behavioral intervention procedure that included exposure to VR, diaphragmatic breathing, diff erential reinforcement, and functional analysis of behavior of participants with public speaking anxiety were investigated. The Virtua Therapy simulator with an Oculus Rift® was used for VR exposure. Six university students participated in the procedure involving the following sequence of sessions: initial interview and baseline measures (3-5), intervention (6), closure (1), follow-up (2). In the baseline sessions, the participants gave a speech in a room without an audience (avatars): in the intervention sessions and follow-up they spoke in a classroom or auditorium with an audience, and verbal consequences (feedback) were provided for appropriate speech pitch and speed. Verbal and non-verbal measures of behaviors were recorded. In the intervention sessions, functional analyses of everyday public speaking situations were performed. There was statistically signifi cant diff erence in the pre-and post-intervention data in the Self-Statements during Public Speaking Scale (improvement in self-evaluation) and improvement in speech quality. The conclusion was reached that the intervention procedure contributed to the reduction of anxiety.