The current study investigated the associations among student perceptions of COVID-19 stress, internalizing problems, and school social support (teacher and classmate support) and how these relations differed across elementary/middle and high school students. Based on data from 526 4th- through 12th-grade students from a school district in the Northeast, we found that COVID-19-related stress was significantly related to internalizing problems for all students, regardless of grade level. We also found that teacher social support, but not classmate social support, buffered the positive relation between COVID-19 stress and internalizing problems. The results of the current study have implications for school psychologists, counselors, social workers, and other educators in alleviating COVID-19-related stress in students and associated symptoms of internalizing problems in students. As the pandemic unwinds, future research should examine the long-term impacts of the COVID-19 pandemic, especially for students with marginalized identities, and how teacher and/or peer support may play a role in buffering these stressors for students.