Background: The COVID-19 pandemic has accelerated the adoption of video consultations in #MentalHealth care, highlighting the importance of therapeutic alliance for successful treatment outcomes in both face-to-face and virtual settings. Telepresence, the sense of being present with the #MentalHealth specialist (MHS) rather than feeling remote, is a critical component of building a strong therapeutic alliance in video consultations. While patients often report high telepresence levels, MHSs express concerns about whether video consultations can replicate the quality of face-to-face interactions. Despite its importance, research on telepresence development in MHSs over time and the dyadic interplay between patients and MHSs remains limited. Objective: This study aimed to evaluate the mutual influence within patient-MHS dyads on telepresence development during video consultations, using data from a randomized controlled trial assessing the feasibility of video consultations for #depression and #anxiety disorders in primary care. Methods: The study included 22 patient-MHS dyads (22 patients, 4 MHSs). Telepresence was measured using the Telepresence in Videoconference Scale. Dyadic data were analyzed using the Actor-Partner Interdependence Model (APIM) with a distinguishable dyad structural equation model. Actor effects refer to the impact of an individual’s telepresence at time point 1 (T1) on their telepresence at time point 2 (T2), while partner effects represent the influence of one party’s telepresence at T1 on the other’s telepresence at T2. Sensitivity analyses excluded data from individual MHSs to account for their unique effects. Results: A significant actor effect for MHSs (P