Telemental health-the use of videoconferencing or audio only (telephone) in mental health care-has accelerated tremendously since the start of the covid-19 pandemic. Meta-analyses have examined the reliability (ie, concordance) of assessment and the efficacy/effectiveness of telemental health compared with in-person care. Results indicate that telemental health assessment and clinical outcomes are similar compared with in-person care but there is much unexplained variability, as well as evidence that patient clinical and demographic characteristics can influence these findings. Further, gaps exist in the literature regarding specific patient populations (eg, psychotic disorders, children/adolescents), treatment modalities (eg, group therapy), audio only telemedicine, and hybrid care that mixes in-person with telemental health care. These gaps provide important directions for the next generation of telemental health research. Comprehensive clinical guidelines from mental health organizations are available to telemental health practitioners and focus on five content themes: legal and regulatory issues, clinical considerations, standard operating procedures and protocols, technical requirements, and considerations of specific populations and settings.