Research on close relationships demonstrates that dyadic convergence, or two people becoming more similar in their experiences and/or beliefs over time, is commonplace and adaptive. As psychotherapy involves a close relationship, patient-therapist convergence processes may influence treatment-specific outcomes. Although prior research supports that patients and therapists tend to converge on their alliance perspectives over time, which associates with subsequent patient improvement, no research has similarly examined belief convergence during therapy. Accordingly, this study focused on patient-therapist convergence in their outcome expectations (OE), a belief variable associated with patient improvement when measured from individual participant perspectives. We predicted both that significant OE convergence would occur and relate to better posttreatment outcome. Data derived from a trial of naturalistic psychotherapy. Patients and therapists repeatedly rated their respective OE through treatment, and patients rated their symptom/functional outcomes at posttreatment. For dyads with the requisite OE data (N = 154), we tested our questions using multilevel structural equation modeling. Counter to our hypotheses, there was no discernable OE convergence pattern over treatment (γ₁₀₀ = 0.01, SE = 0.03, p = .690) and OE convergence was unrelated to outcome at the between-dyad level (γ₀₂₀ = 2.37, SE = 10.28, p = .818). However, on its own, higher early patient OE was significantly associated with better outcome at the between-dyad level (γ₀₅₀ = -0.04, SE = 0.01, p = .007). Results suggest that OE may be more of a facilitative patient versus relational process factor. (PsycInfo Database Record (c) 2022 APA, all rights reserved).