Applied behavior analysis (ABA) is a relevant field for veterinarians helping clients whose animals engage in problem behaviors. In ABA, learning is defined as behavior change due to changes in the environment. Changing behavior then requires changes in conditions. Understanding the importance of control and the difference between emotional behavior and emotional feelings also is informed by ABA. Every behavior intervention should start with a systematic, analytical process called a functional assessment. Behavior change strategies are described, including an ethical procedural hierarchy based on the least intrusive, effective behavior change solution.