Background: The transition to telehealth during the COVID-19 pandemic revealed a lack of preexisting telehealth training for clinicians. As a workplace-based simulation methodology designed to improve virtual clinical skills, announced standardized patients (ASPs) may help meet evolving educational needs to sustain quality telehealth care. Objective: We describe the development and implementation of an ASP program to assess and provide feedback to resident and faculty clinicians in virtual practice, and report on performance, feasibility, and acceptability. Methods: From June 2021 to April 2022, resident and faculty clinicians at a VA primary care clinic participated in a video visit in which an ASP portrayed either a 70-year-old man with hearing loss and hypertension or a 60-year-old man with hypertension and financial stress. Following the visit, ASPs provided verbal feedback and completed a behaviorally anchored checklist to rate telehealth and communication skills, chronic disease management, and use of resources. Domain summary scores were calculated as the mean percentage of "well done" items. Participants completed a feedback survey on their experience. Results: Seventy-six televisits (60 primary care residents [postgraduate year 1-3], 16 internal medicine faculty) were conducted from August 2021 to April 2022. Clinicians performed well in communication skills: information gathering (79%, 60 of 76, well done), relationship development (67%, 51 of 76), education and counseling (71%, 54 of 76), and patient satisfaction (86%, 65 of 76). They performed less well in telemedicine skills (38%, 29 of 76). Participants agreed that the experience was a good use of their time (88%, 67 of 76). Conclusions: An ASP-facilitated training for resident and faculty clinicians assessed telehealth skills and clinical practice and identified areas for intervention. Clinicians responded well to the training and feedback.