In 2017, Team Denmark hosted the Copenhagen Summit on Mindfulness and Acceptance Approaches in Elite Sport. The participants were highly experienced sport psychology practitioners. Most of the participants worked in national elite sport organizations, professional teams or similar, and had several years of experience with supporting athletes during key sporting events such as World Championships and Olympic Games. The summit clearly showed that some of the world’s top sport psychology practitioners have begun to embrace mindfulness and acceptance approaches. Acceptance and Commitment Therapy (ACT) is recognized as an evidence-based practice in mental health treatment by several national mental health boards, including the US-based National Registry of Evidence-based Programs and Practices. The ACT trainer aims to help people engage in actions that bring them closer to living a valued life, rather than just reduce unpleasant internal states. The chapter also presents an overview of the key concepts discussed in this book.