This chapter critically explores the intersection of diversity, inclusion, and fashion advertising through the lens of pervasive systemic biases—referred to as “-isms”—such as ageism, sizeism, ableism, racism, and sexism. Historically, fashion advertising has reinforced narrow ideals of beauty and identity, often excluding or misrepresenting marginalised groups. The chapter details the psychological consequences of such exclusion, including negative impacts on body image, self-esteem, and mental health. Drawing on the self-congruency theory, it examines how congruence between self-image and brand representation influences consumer behaviour and well-being. The chapter also reviews key policy responses, such as advertising standards and legislative measures, along with marketing strategies that promote inclusivity, like diverse casting and influencer collaborations. Through this multifaceted analysis, this chapter argues for a paradigm shift in fashion advertising that fully embraces human diversity. It concludes by outlining a research agenda focused on intersectionality, broader diversity dimensions, and inclusive representation, aiming to build a more equitable and psychologically healthy fashion ecosystem.