While accounting firms are facing recruitment and retention problems, regulatory bodies are calling for efforts to improve diversity to be more effective, especially at senior levels. In this paper, we discuss “merit” and assumptions about “meritocracy” in processes of performance evaluation and career progression. Based on interviews in medium and large professional services firms in the United Kingdom, we explore how the language/practices of merit can inhibit moves to improving diversity. Merit has two aspects: “technical” notions of core competencies associated with merit and cultural notions of social fit, which have the effect of favoring the progression of the elite groups embedded within firms. The latter creates a loop in understanding merit, enacted within firm culture over time, that is difficult to disrupt. As such, efforts to improve diversity are unlikely to bring about change without considering how organizational beliefs about merit have unintended consequences.