Health promotion researchers and practitioners are grappling with how to address growing health inequalities for population groups. In particular, critiques of dominant behaviour change approaches draw attention to the need to engage with social theories to better understand the social and relational drivers of health. Public health researchers are increasingly acknowledging intersectionality as an important theoretical approach, providing a framework for investigating health inequalities by highlighting intersections of individuals' multiple identities within social systems of power that compound and exacerbate experiences of ill health. This article provides an overview of the diverse ways public health researchers and practitioners have applied intersectionality theory to better understand and address health inequalities. We map three key applications of intersectionality theory in public health: As an epistemological approach, as a methodological approach, and as a tool for action and intervention. Drawing on this work, we argue that health promotion researchers and practitioners can enhance engagement with intersectionality theory to address important challenges within the field. Through this article, we aim to inspire the continued exploration of intersectionality and offer some insights into opportunities and challenges for doing so in health promotion.