Behavior Modification is defined as the use of rewards or punishments to reduce or eliminate problematic behavior, or to teach an individual new responses to environmental stimuli. Three tools used in Behavior Modification are positive and negative reinforcement and cueing.

The goal of a program of behavior modification is to change and adjust behavior that is inappropriate or undesirable in some way. When embarking on a program of behavior modification it is important is that the undesirable behaviors be isolated and observed. With this observation comes awareness of the behaviors, on the part of both the parent and teacher and also on the part of the individual whose behavior is being modified. With this awareness, comes a greater goal of understanding the cause and effect of the behaviors, and thus affect change.

In many cases, some form of behavior modification along with cognitive therapy and medication therapy are the preferred methods of treatment for disorders such as AD(H)D, and Conduct Disorders. Behavior modification and cognitive therapy are the principle forms of treatment for disorders such as Eating Disorders and Substance Abuse.

Simply put, behavior modification therapy is based on the idea of antecedents (events that occur before a behavior is apparent), and consequences (the events that occur after the behavior occurs). The appropriate behavior is learned by observing and changing both the antecedents and the consequences of the behavior so that the appropriate behavior increases and the inappropriate behavior decreases.