The COVID-19 pandemic disrupted mental health services delivery across the US, but the extent and implications of these disruptions are unclear. This retrospective observational analysis used the claims clearinghouse Office Ally to compare outpatient mental health services use from March to December 2016-18 against use during the same period in 2020. We identified encounters for people ages twelve and older with primary diagnosis codes corresponding to mental health conditions and categorized encounters as in-person or telehealth, using Current Procedural Terminology and place-of-service codes. In-person mental health encounters were reduced by half in the early months of the pandemic, with rapid recovery of service delivery attributable to telehealth uptake (accounting for 47.9 percent of average monthly encounters). We found variation in the degree to which telehealth use increased across groups: People with schizophrenia made up a lower proportion of telehealth encounters relative to in-person visits (1.7 percent versus 2.7 percent), whereas those with anxiety and fear-related disorders accounted for a higher proportion (27.5 percent versus 25.5 percent). These findings highlight the importance of broadening access to services through new modalities without supplanting necessary in-person care for certain groups.