Higher education institutions have acknowledged the importance of social networks for multiple purposes, such as exploring innovative mechanisms for teaching-learning processes, colonizing new social communication channels and strengthening their institutional brand. The primary aim of this study was to identify the impact of various post formats on digital engagement in the context of the Facebook pages of some of the most important Mexican universities. It likewise sought to evaluate the use that universities made of each format. A quantitative methodology was used to analyse 31,590 content units posted by 28 universities, resulting in a total of 1,270,621 likes, 252,399 shares, and 80,620 comments on their respective Facebook pages. The study found that: a) there is a statistically significant relationship between a post’s format and the digital engagement it generates; b) while links are the least conducive format for boosting digital engagement, they are also the most frequently used; and c) although images usually boost digital engagement the most, only 18% of the studied universities chose this format first.