Facilitating the learning and engagement of students with attention-deficit/hyperactivity disorder (ADHD) in any classroom can be challenging. In this study, we examined the use of online daily behaviour report card (DBRC) to decrease off-task behaviour in students with ADHD who were studying at a public school for at-risk youths in Singapore. Using a multiple baseline design across participants, the study involved 3 adolescents with ADHD who exhibited a high level of off-task behaviour and had received numerous office discipline referrals. Aside from the involvement of classroom teachers, the online DBRC intervention was modified to involve an additional school mentor who supported the parents in monitoring and guiding the students. Results indicated that the online DBRC intervention had been effective in decreasing off-task behaviour in the 3 students. Implications of findings and directions for future studies are discussed.