This study advances a theoretical model centered on collective and internal efficacy to explain the separate pathways through which political sharing on Facebook and Twitter may influence individuals to engage in political activities. We test the model with data from a 2‐wave panel survey conducted with an adult population in 2013 in Chile. We found that frequent usage of Facebook and Twitter for sharing political information is conducive to higher levels of participation through different efficacy measures. Facebook has a significant effect on collective—not internal—efficacy, whereas Twitter's effect is on internal—not collective—efficacy. Results are discussed in light of the diverse affordances and strengths of network ties of Facebook and Twitter.