Depression remains underdiagnosed and subsequently undertreated in primary care settings. This is despite its high prevalence within Western countries such as the United Kingdom (Thornicroft, 2017). Black minority ethnic individuals are less likely to be diagnosed and treated for depression compared with White ethnic individuals. However, evidence suggests that they are at increased risk due to factors such as discrimination (Barnes & Bates, 2017). This thesis aimed to explore primary healthcare professionals (PCPs) and individuals who self-identified as Black African and Christian experiences of the diagnostic process for depression. Part A presents a systematic review using a narrative synthesis to explore how PCPs approach the diagnostic and management processes of depression in Black minority ethnic patients. The findings suggests that PCPs perceived patient-related factors such as stigma towards depression as a diagnostic label further complicates the diagnostic and management processes in this patient group. This is further compounded by PCPs adherence to conceptualise and manage depression in line with the dominant westernised biomedical model. This subsequently creates tension between PCPs and their patients. However, some PCPs demonstrate culturally appropriate care to mitigate this complexity. Further research is required to examine how such care is implemented by these professionals. Part B presents an empirical paper using an interpretative phenomenological analysis to explore how Black African individuals who also identify as Christian experience receiving a diagnosis of depression. The findings suggest that these experiences were shaped by religious and cultural beliefs about depression, help-seeking, and depression as a diagnostic label. These beliefs evolved dependent on individuals’ connection to God and systemic influences. Interactions with healthcare professionals either complicated or eased the diagnostic process for these individuals. Clinical implications included the role of relational continuity between GPs and their patients, and the role of clergy to normalise depression further within the Black and Christian communities.