Research and policy dialogue surrounding absenteeism has predominately focused on the school when it comes to reducing student absences, with little focus on the classroom. Further, there has also been minimal attention paid to effects of absenteeism beyond achievement outcomes. To address both, we focused on the classroom and asked whether classrooms with typically higher rates of absenteeism were linked to students’ individual achievement, executive function, and social skills. We used a nationally representative dataset of children who started in kindergarten in 2010–2011 (N = 18,170) – when absenteeism is at its highest point not seen again until adolescence. Using school and student fixed effects, our findings revealed that as the percent of absent classmates increases, individual student performance worsens consistently across achievement and executive function domains. Evidence for links between classmate absenteeism and student performance in socio-behavioral domains was less conclusive. Finally, the findings were unique to different student groups. (author abstract)