The study aimed to highlight the relationship between self-directed learning and academic achievement and the comparison of self-directed leaning via online and conventional university learning. A self-developed survey was used to collect data from online distance and conventional leaners. All the students of the Faculty of Education of one online and one conventional degree awarding universities were the population of this study. There were 1139 students enrolled in online and 1809 students enrolled in conventional degree awarding universities in the Faculty of Education for Spring 2019. A sample of 590 students (20% of population) out of total 2948 students were selected, using a simple random sampling technique. Data was analyzed by using t-test, Pearson r to find out relationship between variables. Findings indicate significant difference between SDL of online and conventional university students. Also, co-relation of SDL with academic performance is high in students learning via online contrary to that of conventional university students. The study suggests that using SDL as teaching approach to develop students' abilities to self-regulate their teaching-learning process.