Purpose – Cases of corruption, embezzlement, theft and fraud, abuse of discretion, favoritism, nepotism, clientelism, and abuse of power in governments have led to a growing demand from society to access public information. In response to this demand, governments have been forced to be more transparent in the conduct of their activities. The information transparency index (TI) may be conditioned by economic and political characteristics of local governments affecting the information provided. What factors influenced the index of municipal transparency? Literature about transparency is largely based on the explanations of the agency theory and the legitimacy theory. Based on the postulates of both theories, the purpose of this paper is twofold. First, study the index transparency in Spanish municipalities, and, second, determine the main features that are affecting the index of transparency. Design/methodology/approach – Data were collected from Transparency International Spain ranking and from official so...