The current study aimed to investigate the effectiveness of the Self-directed Learning (SDL) process on multimedia competencies of educational technology students at Arak university in Iran. The sample of the study consisted of all educational technology students studying at Arak university. The sample included students who were selected for project courses in the second semester of academic year 2014-2015. The quasi-experimental research, pre-test, post-test design was used for the study. Before the treatment, the pretest of multimedia competencies was employed, then students in the project course received education through the SDL process. The period lasted for 13 weeks, then the post-test was conducted. For data collection, the researchers prepared a questionnaire of multimedia competencies with three subscales (multimedia instructional design, multimedia production skills, and multimedia production tools). The validity of the questionnaire was confirmed by experts in the field of Educational Technology, and Cronbach's alpha coefficient was obtained as a reliability of 0.90. The data were analyzed with independent and paired-samples t-test. The results showed that there was a significant difference between students’ scores in pre-test and post-test; and there was no significant difference between male and female students’ scores on multimedia competencies.