What is the social, emotional, and academic impact of attending school remotely rather than in person? We address this issue using survey data collected from N = 6,576 high school students in a large, diverse school district that allowed families to choose either format in fall 2020. Controlling for baseline measures of well-being collected 1 month before the onset of the COVID-19 pandemic as well as demographics, high school students who attended school remotely reported lower levels of social, emotional, and academic well-being (effect size [ES] = 0.10, 0.08, and 0.07 standard deviations, respectively) than classmates who attended school in person--differences that were consistent across gender, race and ethnicity, and socioeconomic status subgroups but significantly wider among 10th-12th graders than ninth graders.