The goal of this study was to test the efficacy of training community-based psychotherapists who were part of a practice research network to be more attuned to their patients' experiences of the therapeutic relationship. We were particularly interested in the effect of therapist training on the congruence of alliance ratings with their patients. Forty psychotherapists who treated 117 patients were randomly assigned to receive either no training or training, whose learning objectives were to help therapists to develop and maintain a therapeutic alliance. The training included workshops and ongoing consultations to help the clinician to strengthen the therapeutic relationship with the use of mentalizing, attachment theory, countertransference management, and metacommunication. Therapeutic alliance and well-being outcomes were measured at each of six consecutive early psychotherapy sessions. We used the truth and bias model and response surface analysis within a multilevel modeling context to test hypotheses. There was a significantly faster rate of alliance growth in the training versus the no training condition when the alliance was rated by therapists, but not when rated by patients. Trained therapists experienced greater temporal congruence in alliance ratings with their patients compared to untrained therapists. Patient well-being outcomes improved in a session when trained therapists and their patients agreed in their positive alliance ratings in a previous session. This association not significant among untrained therapists. Training therapists in key interpersonally focused skills may lead them to be better attuned to their patients' experiences of the therapeutic relationship. (PsycInfo Database Record (c) 2023 APA, all rights reserved).