The Information and Communication Technology (ICT) supported by the internet, like social media, are contemporary media and have altered the modes of relationship between individuals and between individuals and organizations, and governments are aware of this tendency (Rothberg & Valença, 2014; Dadashzadeh, 2010; Mergel, 2010; 2012; 2013a; 2013b; Cunha & Miranda, 2013; Bonsón, Royo & Ratkai, 2014; Ma, 2017). Public organizations have envisioned possibilities to promote social participation through social media, notably Facebook. In this scenario, different users react differently to the content they are exposed to, presenting levels of interaction that are not always compatible with what was expected. It is important, then, to understand the factors that condition this process of interaction, here called engagement, through the identification of its characteristics and form of influence. In this context, this article proposes a model of analysis (framework) of the conditioning factors of social media engagement in the public sector, based on five explanatory dimensions: individual, organizational, communicational, technological and environmental.