Teachers with an autonomy-supportive style rely on different instructional behaviors to motivate their students than do teachers with a controlling style. In the present investigation, the authors tested which of these instructional behaviors actually correlated positively or negatively with students' autonomy. The authors used Deci, Spiegel, Ryan, Koestner, & Kauffman's (1982) teacher-student laboratory paradigm to randomly assign 72 pairs of same-sex preservice teachers into the role of either teacher or student. From videotapes of the 10-min instructional episode, raters scored 11 hypothesized autonomy-supportive behaviors and 10 hypothesized controlling behaviors. Correlational analyses confirmed that students perceived the functional significance of 8 instructional behaviors as autonomy supports and 6 instructional behaviors as autonomy thwarts. The discussion focuses on the interpretation and classroom implications of these data.