Client-therapist synchrony in various channels (e.g., self-reported affect or physical movement) has been shown as a key process in the construction and development of therapeutic alliance. However, psychophysiological synchrony between clients and therapists has been understudied, with the few extant studies typically relying on single-session data, and no studies examining it within the context of emotion-focused techniques. The main aim of the current paper is to examine the role of client-therapist physiological synchrony during segments of one emotion-focused technique-namely, imagery (IM) work-in predicting therapeutic alliance, and to compare it to the role of synchrony during segments of more traditional cognitive-behavioral (CB) techniques. We conducted an open-trial study in which 31 clients with test anxiety received a 6-session protocol-based treatment. Both clients' and therapists' electrodermal activity (EDA) were continuously assessed during sessions. The physiological measures for 5 sessions each (N = 128) were used to compute client-therapist synchrony in IM and CB segments. Therapeutic alliance was assessed using the Session Alliance Inventory. Client-therapist dyads' synchrony during IM and CB segments was, on average, greater than chance. Synchrony varied mostly at the session (vs. the dyad) level. Multilevel analyses revealed that the synchrony within IM segments (but not within CB segments) was significantly associated with the therapeutic bond aspect (but not the task/goal aspects) of alliance. Physiological synchrony during emotion-focused IM is tied to the bond component of the therapeutic alliance at the session level. (PsycINFO Database Record (c) 2019 APA, all rights reserved).