Maladaptive behaviours of students with Attention Deficit Hyperactivity Disorder (ADHD) is negative behaviours, which disturb a learning process in the classroom. This study was conducted to identify the use of the behavior contract in reducing maladaptive behaviors in students with ADHD in Al Firdaus Elementary School Surakarta, Indonesia. Subject of this study was a third grade ADHD student. The Single Subject Research (SSR) with multiple  baseline cross variables design was applied as experimental method. The target behaviors were directly observed,
recorded in the instrument and analyzed by visual graphic analysis method. At the baseline-1 phase, the target behavior of verbally disrupting friends occured on average 20 times, while nonverbal disruption occured 24 times. The target behavior in the intervention -1 phase tended decrease, with an average of 5 times (verbal) and 4 times (nonverbal). At the baseline-2 phase, the target behavior of interrupting the teacher’s explanation occured on average 18 times. This behavior decreased in the intervention-2 phase with an average of 3 times. At the baseline-3 phase, the
target behavior of unable to resist eating and drinking occured on average 10 times. At the intervention-3 phase, the behavior occured on average once. It can be concluded that the behavior contract may reduce maladaptive behaviors of student with ADHD. 

Keywords:Behavior Contract, Maladaptive Behavior, ADHD.