This edited collection will introduce the key principles for providing interventions with support teams of all kinds who work with people with intellectual disabilities (ID). These teams will often be part of external organisations, and despite this indirect work being an important part of working psychologically with people with ID, there is little in the way of evidence-based practice in this field largely due to variations in practice. Informed by practice-based evidence, this book will introduce the foundational principles that can be applied before moving to chapters that focus on specific theoretical and therapeutic approaches such as Cognitive Analytic Therapy, Compassion Focused Therapy and Positive Behaviour Support interventions, with case examples and practice guidance offered to support the application of these ideas into practice.