This Statistics in Brief explores teacher autonomy in the classroom during the 2003-04, 2007-08, and 2011-12 school years. Using data from the National Center for Education Statistics (NCES) Schools and Staffing Survey (SASS), the Statistics in Brief examines a construct of teacher autonomy based on teachers' responses to six questions regarding perceptions of influence over classroom instruction and classroom management. The brief focuses on how teachers' perceptions of autonomy have changed over these three school years, as well as how levels of teacher autonomy vary across selected teacher and school characteristics. This brief reports the percentage distribution of perceived autonomy for each characteristic presented (i.e., each characteristic sums to 100 percent across the three levels of autonomy). For example, the percentages of public secondary school teachers who perceived high, moderate, or low autonomy in the 2011-12 school year were 16, 65, and 19 percent, respectively, which captures 100 percent of public secondary school teachers. This full distribution by characteristic allows comparison between levels of autonomy in one year and comparisons for a specific level from year to year. The following are appended: (1) Data Tables; and (2) Standard Error Tables.