To examine the organizational characteristics associated with telemedicine services provided by mental health care organizations before and after onset of the COVID-19 pandemic in the United States. Using 2019-2020 National Mental Health Services Survey data, we assessed changes in provisions of telemedicine services by mental health care facilities before and after onset of the COVID-19 pandemic. We estimated multivariable logistic regression models comparing pre- vs postpandemic changes in prevalence of telemedicine offered by mental health care facilities. We incorporated mental health care organizations' characteristics, including facility type, accepted payment, geography, and language service provisions, as well as state-level policies, such as payment parity laws, shelter-in-place laws, and number of COVID-19 cases. Mental health care facilities had 4 times the odds (odds ratio [OR], 4.3; 95% CI, 4.09-4.61) of telemedicine provision post pandemic in 2020 compared with prepandemic in 2019. In 2020, facilities that accepted Medicaid (OR, 1.3; 95% CI, 1.11-1.49) and Medicare (OR, 1.3; 95% CI, 1.14-1.39) were more likely to provide telemedicine than those that did not. Facilities that offered American Sign Language (OR, 1.3; 95% CI, 1.16-1.43) and non-English language services (OR, 1.3; 95% CI, 1.15-1.44) were more likely to provide telemedicine than facilities that did not. Facilities located in states with payment parity laws (OR, 1.2; 95% CI, 1.11-1.36) were more likely to offer telemedicine than states without. Telemedicine availability in mental health facilities has expanded post COVID-19 pandemic, but telemedicine provision has been uneven across organizational and state-level factors. Expansion of regional investments and payment parity might be necessary to ensure equitable provision of telemedicine.