This study explores the use of Facebook by political actors in election campaigns, establishing the extent to which candidates, parties and citizens engaged in online participation through different online tools provided by this social networking site. A comparative content analysis of the Facebook pages of the main candidacies in the election campaigns in Spain (Castilla y León) and Mexico (Nuevo León) in 2015 was carried out. The results reveal a positive relationship between types of engagement, especially in the Mexican campaign, where politicians and users score systematically higher in all variables measuring engagement. However, results also indicate that the citizen engagement was of higher quality/ intensity in the Spanish campaign.