The effect of remote learning on student performance has been a frequent topic of research and discussion in the aftermath of the COVID-19 pandemic, yet little is known about the impact of remote instruction on the performance of teachers. This study documents how relative effectiveness of teachers changed when moving from in-person to remote instruction and analyzes the characteristics of teachers associated with greater relative effectiveness during remote instruction. Using matched student/teacher-level data from three large metro-Atlanta school districts, we estimate teacher value-added models to measure the association between teacher characteristics and a teacher's relative contribution to test score growth before and during the period of virtual instruction in the 2020-21 school year. We find evidence of increased variation in overall teacher effectiveness during remote instruction. Results are driven by veteran teachers, who appear relatively more effective in virtual instruction than their less-experienced peers, and by the very best in-person teachers, some of which experience large declines in relative effectiveness when shifting to remote instruction.