Oppositional-defiant disorder (ODD) is characterized by a recurrent pattern of developmentally inappropriate levels of negative, defiant, disobedient, and hostile behavior toward authority figures. Behaviors associated with ODD include temper tantrums; persistent stubbornness; resistance to directions; unwillingness to compromise, give in, or negotiate; deliberate or persistent testing of limits; and verbal and minor physical aggression. The usual treatment approach for children with ODD is parent management training (PMT). PMT primarily involves teaching parents strategies to respond consistently and correctly to their child's behavior. However, PMT does not always lead to longstanding results and there is a need for alternative treatments. Collaborative problem-solving (CPS) is a treatment approach that involves both the parent and child by teaching parents to help their child control their emotions and to problem-solve as a family. This study will compare the effectiveness of CPS and PMT in treating children with ODD.