Much of the research on gender and diplomacy has focused on those already let into the ‘club’. This article analyses the ‘threshold’ to diplomacy: security clearance processes. Security vetting ultimately determines who progresses, and what level of clearance (and therefore seniority or position) a diplomat can achieve. This article seeks to trace the journey for individuals entering a diplomatic career. It argues that security vetting is simultaneously based on legitimate processes for assessing potential national security threats, and on values interpretation (such as loyalty, maturity and trustworthiness) which may invite bias or lead to illegitimate processes of exclusion. By excavating the gendered history of vetting, we can better understand the limitations of the current de-historicised and ‘impartial’ process. We argue that clearance processes have not sufficiently evolved over the past decades of social progress, which has negative implications for the evolution of diplomacy as a social practice.