ABC is an acronym for Antecedents, Behavior, Consequences. It is used as a tool for the assessment and formulation of problem behaviors and is useful when clinicians, clients, or carers want to understand the ‘active ingredients’ for a problem behavior. The ABC Model worksheet can be used to identify the triggers for a behavior by monitoring environmental (e.g., location, company, time of day, visual and auditory stimuli) and internal circumstances (e.g., emotions, body states, thoughts, memories) which occur before the behavior. Attention is also then drawn towards the consequences of the behavior: both short-term and long-term, intended and unintended. The ABC technique is used across a wide variety of settings. These include clinicians working with verbally capable adult clients, carers working in residential settings, parents who want to better understand their child’s behavior, and teachers trying to understand problem behavior in the classroom. When working with clients who are able to engage with talking therapies and reflect on their behavior, the ABC Model is a helpful tool for building the client’s awareness of the triggers for their behavior, and the consequences of their actions. When working more cognitively, some clinicians choose to adapt the model slightly to explore the sequence: Antecedents > Beliefs (Thoughts) > Consequences.