In school classes students influence each other at conscious and subconscious levels and therefore, students' shared perceptions are considered meaningful for the development of the individual student. This article identified situations where students' class-average perceptions of autonomy support add to the predictive validity of students' individual perceptions for their intrinsic motivation (i.e., a contextual effect). Specifically, we compared contextual effects of perceived autonomy support on intrinsic motivation in familiar and unfamiliar situations. Familiar situations were represented by mathematics classes at grades six, seven, and eight, because this subject is taught from grade one on. Because in Austria physics classes usually start only at grade six and chemistry classes usually start at grade eight, these classes were considered unfamiliar situations. We found that students' class-average perceptions of their teachers' autonomy support predicted intrinsic motivation only in unfamiliar situations (i.e., in the first and in the second year after a subject was newly introduced). These findings are discussed regarding their meaning for educational practice.