Persistent underrepresentation of ethnic minority professionals in senior leadership roles within educational institutions remains a pressing concern across the United Kingdom and comparable contexts. Existing research has often emphasised representation gaps, yet limited attention has been given to the structural and cultural mechanisms that sustain these inequalities. This paper develops a critical conceptual analysis of systemic and cultural barriers shaping leadership access and progression. Drawing on organisational theory, critical race perspectives, and empirical insights from previous research, the analysis demonstrates that leadership inequality is not simply the result of individual deficits or pipeline limitations. Instead, it reflects deeply embedded institutional processes, including biased recruitment pathways, informal sponsorship patterns, and culturally constructed standards of leadership legitimacy. The paper further argues that cultural expectations surrounding authority, communication, and professional identity continue to privilege dominant groups while marginalising alternative leadership expressions. These dynamics operate simultaneously, producing cumulative disadvantage across career trajectories. The contribution of this paper lies in reframing ethnic minority underrepresentation as a structural and cultural phenomenon rooted in institutional design rather than an outcome of insufficient diversity initiatives. The analysis concludes by outlining implications for leadership theory and institutional reform, emphasising the need for systemic transformation that addresses both formal processes and informal norms.