The third edition of this award-winning textbook provides an accessible and engaging introduction to the field of LGBTIQ+ psychology. Comprehensive in scope and international in outlook, it offers an integrated overview of key topical areas, from history and context, identities and fluidity, families and relationships, to health and wellbeing. This third edition includes updates across all chapters that provide a greater focus on diversity and utilize new terminology throughout to reflect changes in the field. It addresses recent developments in the field of trans studies, and explicitly references emerging work around pansexuality and asexuality. An entirely new chapter focuses on a diversity of topics receiving increased attention including LGBTIQ+ people in foster care, LGBTIQ+ refugees, disabled people accessing services, and trans and intersex people in sport. The fallout of increasing far-right extremism in Europe and America is also discussed. This groundbreaking textbook is an essential resource for undergraduate courses on sex, gender and sexuality in psychology and related disciplines, such as sociology, health studies, social work, education and counselling.