The dissertation investigates the origins, implementation, and effects of transparency in development aid. Transparency is a key tenet in most contemporary governance reforms because of its inherent value and expected instrumental benefits. Under the auspice of transparency, standardized information disclosure practices – an increasingly common yet understudied form of transparency – are being deployed in the development field to improve governance. The relationship between disclosing information and improved aid is, however, conceptually unclear, underspecified, poorly validated and arguably problematic. This research tackles these issues by identifying the origins of aid transparency, theorising the global architecture for information disclosure and investigating its consequences for governing. The approach of the dissertation is institutional, emphasising the steering influences of the imperative to disclose data. The research builds on a multi-method design with four empirical parts. The first part explores how information sharing developed into a global norm. The second part consists of two donor case studies that consider what aid transparency entails in practice. The third part links information disclosure and aid governance qualities through quantitative analysis to pinpoint what kind of governing information disclosure contributes to. The fourth part inspects how information disclosure over time generates implicit conditionalities in global aid flows. The thesis argues and shows empirically that the spread of aid transparency contributes to a self-perpetuating form of aid governance where donors disclose to obtain evidence and seek evidence to be able to disclose. This elusive quest for evidence has political implications as it shapes who gets funds. The unfortunate risk of the openness paradigm is pushing the development field towards two-tiered aid governance where those recipients that possess the institutional capabilities to partake data-dense governing benefit disproportionately compared to others, who are left to fend for themselves or rely on alternative funding from outside of the Western, data-obsessed donor establishment.