This study investigated the relationship between Social Network Service (SNS) fatigue and behaviors of academic procrastination and learning flow among university students. Furthermore, the frequency and duration time of SNS use were studied with regrad to in its relations with the two variables. For the purpose of the study, data were gathered from 267 students (average age=21.17, S.D=2.344) enrolled in three universities located in Seoul and Pusan through online survey. The data were analyzed by use of statistical package SPSS 22.0 for correlation and multiple regression analyses. Following are the results of the data analyses. First, the variable of SNS fatigue was found to be significant in affecting students’ behaviors of academic procrastination while its effect was not proved with regard to learning flow. Second, the frequency of SNS media per day had negative effect on students’ learning flow. Third, the duration time per individual SNS use had nothing to do with either academic procrastination or learning flow. These results made it possible to suggest the following. First, students need to be informed or educated about the effect of SNS fatigue for preventing themselves from its negative effect on their management of academic behaviors. Second, the negative effect of SNS media had more to do with its frequency of use than its duration time, thus it is highly required for university students to grow self-regulation especially in the time of test preparation or performing academic tasks. Finally, we suggested future research concerning the mediating effects of the characteristics of research participants including sex or other socio-psychological variables in investigating the relations between SNS fatigue and students’ learning.