This study investigated practices in self-contained high school classrooms serving students with significant cognitive disability (SCD). Nineteen students and nine teachers across five high schools participated. A time-sampling method was used to describe the ecological, teacher, and student behaviors of these classrooms. Field notes were collected and analyzed as well. Results revealed students in these classrooms were often passively engaged and had few opportunities to learn from rigorous curriculum. Instructors engaged in few practices known to be effective in supporting the learning of students with significant cognitive disabilities. Finally, the classrooms themselves were often distracting and demonstrated little evidence of specialized or effective instruction. Implications for teaching and research are included.