People in modern society are media multitaskers due to portable devices and omnipresent wireless networks, and college students are no exception. Previous studies have indicated that students' media multitasking behaviours in class harm their academic performances, and understanding the reasons for college students' engagement in such behaviour is meaningful. However, the literature takes media multitasking behaviour as an audience behaviour, which ignores the interaction between students and their surroundings. This study fills this gap by emphasizing the role of the social learning process. A survey was conducted in a public and comprehensive university in western China, and a total of 457 valid respondents were obtained. The results from PLS-SEM revealed that college students' in-class media multitasking behaviours were influenced by both observational learning (ie, imitating others) and reinforcement learning (ie, in-class interventions), and this learning process was shaped by students' media multitasking self-efficacy and self-management of learning. These findings contribute to the current literature by providing a relatively new perspective for understanding college students' in-class media multitasking behaviours, and suggestions about how to deal with such behaviours are also provided.