This study sought to systematically examine the academic behavior of children with ADHD in different instructional contexts in an analogue classroom setting. A total of 33 children with ADHD participated in a reading comprehension activity followed by a testing period and were randomly assigned within days to either small-group instruction, whole-group instruction, or independent seatwork. The effects of instructional contexts on on-task behavior during instruction and on-task behavior and work productivity during testing were examined. Children with ADHD were found to be more on task during small-group instruction than both whole-group and independent seatwork instructional conditions. In the testing context, children with ADHD were found to be less productive in small-group than in the whole-group and independent seatwork conditions. The findings of this study have implications for future research evaluating the standard educational practices and accommodations made for children with ADHD in the classroom setting. (Contains 2 tables.)