One of the main objectives of the present report, Connecting Theory, and Practice: Report on the Best Full Spectrum Harm Reduction Practices Survey, is to gather insights and experiences from PWUD including young people, harm reduction practitioners, peers, policy advocates, social workers, and researchers worldwide, with a particular focus on the Global South perspectives, while still ensuring the inclusion of the Global North, capturing challenges, innovative strategies, and best practices that address the wide-ranging needs of YPWUD.