The relations between students' value orientations, decisions in conflicts between on-task and off-task actions in the classroom, and experiences of motivational interference following these conflicts were investigated. It was expected that well-being value orientation was positively linked and achievement value orientation was negatively linked to decision for off-task behavior in such conflicts and that the higher students' well-being value orientation, the higher their motivational impairment when deciding for the on-task behavior and the lower when deciding for the off-task behavior. For achievement orientation, the relationships were predicted to be reversed. The experience of motivational interference while performing on-task behavior was, in turn, expected to be related to worse grades. Data from 817 students (mean age 13.44) from 35 classrooms were collected using self-report questionnaires and analyzed in a series of hierarchical linear models. Analyses showed the relationships as predicted. All relationships found were comparable to the relationships found for a conflict between school and leisure actions after class. Results point out that even if students resist the off-task temptation in class, the mere possibility of off-task behavior can impair motivation and achievement.