Inequalities in marginalised groups are observed to be worse across health outcomes, including mental health. It could be that those from marginalised groups experience difficulties in forming strong therapeutic alliances with their therapists, who may be hold identities from dominant or privileged groups. This thesis aimed to examine the research into applying intersectional cultural humility in clinical practice and proposed that a novel tool of intersectional cultural humility is needed to provide practitioners with structured methods of considering this concept within their therapeutic work. Part A of this portfolio presents a conceptual review of the literature around the therapeutic alliance, intersectionality, and cultural humility. It defines principles of cultural humility and examines existing frameworks and methods of considering cultural humility and intersectionality within clinical practice. The findings of this review suggest a tool is needed to aid clinicians in aligning with an orientation of intersectional cultural humility. The review concludes with suggestions for the development of a tool and the key concepts underlying it, as well as potential barriers to using the tool. Part B of this portfolio is an empirical study that investigated the subjective experiences of trainee clinical psychologists using a proposed tool of intersectional cultural humility that has been developed following the conceptual review. The findings suggested that participants found the tool helpful for structuring reflections on intersectionality. Participants reflected on barriers to using the tool, which could include inaccessible language, discomfort, and time constraints. Participants made suggestions for embedding the tool in clinical training settings and directions for future research in order to test the value of this tool in promoting intersectional cultural humility.