Social media has become an important tool for universities to implement strategies to promote, position and differentiate their brand identity, to establish and foster the communicative relationship with their stakeholders. This study explores the interactivity strategy developed in digital communication by 70 leading universities from Europe, the United States and Latin America. A specific quantitative methodology was designed to analyze the universities' social media publications (90,241). The general communicative approach and the communication resources applied were studied through quantitative content analysis. Results show that the universities have an informational approach in their publications on social networks, with little differences among regions and platforms. Expositive and interactive resources are being used in a broad, integrated manner although there are some differences in each region and social network. Thus, the universities opt for a monological interactivity strategy in their digital institutional communication, with little differences between social networks. They are changing toward a model that continues to prioritize dissemination of information, but it is evolving toward more combination of various communication resources that make content more attractive to their publics. This research provides insights into interactivity strategies used by universities on social networks to develop effective digital communication strategies for enhancing engagement with publics.