The study aimed to investigate a causal model that explains the relationships between Online Vigilance (Salience, Reactibility and Monitoring) and Media Multitasking as independent variables and Mind wandering (related to the topic-unrelated to the topic) and Academic procrastination as mediating variables and Academic Achievement as dependent variables among university students in a sample of (389) third year students in Faculty of Education, Benha University, during the academic year (2022/ 2023), The results indicated that: There are direct positive effects of the three dimensions of online vigilance on the two dimensions of mind wandering. There is a direct positive effect of the salience dimension on academic procrastination, and an indirect effect of the reactibility dimension on academic procrastination across the two dimensions of mind wandering. There are direct and indirect negative effects of the salience dimension on academic achievement across the two dimensions of mind wandering and academic procrastination, and negative indirect effects of the two dimensions (reactibilitymonitoring) on academic achievement across the two dimensions of mind wandering. There is a direct positive effect of media multitasking on both dimensions of mind wandering. There are positive direct and indirect effects of media multitasking on academic procrastination across both dimensions of mind wandering. There is a negative indirect effect of media multitasking on academic achievement across both dimensions of mind wandering and academic procrastination. There are direct positive effects of the two dimensions of mind wandering on academic procrastination. There is a direct negative effect of the topicrelated mind wandering dimension on academic achievement. There is an indirect negative effect of unrelated mind wandering on academic achievement through academic procrastination. There is a direct negative effect of academic procrastination on academic achievement.