Previous research has demonstrated that student motivation and engagement can take different forms across a variety of tasks at school or college. However, no research has yet examined the forms of student momentary engagement that emerge in response to a single task. Adolescent students (N = 196) from two low-income secondary schools in Dublin, Ireland were given the same English grammar task to complete in a 10-min period. We used systematic observation and posttask self-report measures to collect data on momentary cognition, emotion, motivation, and behavior. Using latent profile analysis, we discovered seven main forms of momentary (dis)engagement: fully engaged, attentive but amotivated, attentive but disinterested, attentive but disaffected, distracted but motivated, disengaged, and deeply disengaged. Gender, ethnicity, academic self-efficacy, peer support, and classmate cognitive engagement were notable predictors of group membership. The results should be useful to educators wanting to understand why students in their classrooms have a variety of responses to the same task.