Acceptance and Commitment Therapy (ACT) is an evidence-based psychological intervention that cultivates psychological flexibility—the ability to stay present, open to experience, and take values-driven action even in the presence of difficult thoughts and feelings. Developed by Steven Hayes and colleagues in the 1980s, ACT operates through six core processes organized in the Hexaflex model, targeting both mindfulness and behavioral change. Unlike traditional approaches that attempt to reduce or eliminate symptoms, ACT teaches workability: asking "Is this working to create the life you want?" rather than "Is this thought true?" This mindset shift—from struggling against internal experiences to making room for them while pursuing what matters—makes ACT uniquely applicable to anxiety, depression, chronic pain, relationship challenges, and everyday stress.