This paper serves as a double purpose in the context of local administrations’ information on line disclosure of Social Responsibility (SR). First, this study examines how levels of information dissemination of SR are evolving. Second, some fiscal, political, population, and socioeconomic factors were investigated as determinants of this information disclosed. A content analysis of the websites of the local government in a region of Spain was carried out. This region is the first which has a Corporate Social Responsibility Lay. Later, according to literature review, the authors propose a multiple linear regression model based on disclosure index scores calculated previously. On the one hand, the results show an increase in the amount of SR information disclosed between 2013 and 2016. On the other hand, the study concludes that larger municipalities with more resources, progressive party governments, and intense political competition present higher levels of information disclosure of social responsibility.