Transparency in public administration is essential to ensure that the government serves the interests of society, allowing citizens (users) to know how public funds are spent. This promotes accountability and responsibility among elected leaders, strengthening citizens’ trust in the government. In Brazil, laws have shaped transparency through Transparency Portals. However, these portals face challenges such as the accuracy and reliability of the information, as well as issues related to usability, interactivity, and accessibility. In this context, this research presents the process of validating specialized Guidelines for Transparency Portals. Usability tests evaluated the efficiency, effectiveness, and user satisfaction in completing tasks, identifying necessary improvements. It is estimated that such Guidelines can significantly contribute to public sector IT professionals in developing more accessible and intuitive Transparency Portals, facilitating social control and the exercise of citizenship.