AA-HA! 2.0 offers insights into the current health and well-being landscape of the world’s over 1.2 billion adolescents, underlining evidence-based solutions and presenting strategies for priority setting, planning, implementing, and evaluating health and well-being programmes. The inclusion of key implementation strategies and real-world case studies make this guide a practical tool for governments in designing and implementing a new generation of adolescent health and well-being programmes. Building on the solid foundation of the first edition and voices of adolescents and young adults around the world, this multi-agency product has evolved to incorporate valuable learnings from the past six years, including of the COVID-19 pandemic's impacts. Latest estimates of mortality and disease burden, updated evidence, and a broader focus on well-being make our second edition a cutting-edge resource for policy makers in the area of adolescent health and well-being.