This quantitative study focuses on online metacognitive reading strategies used by 39 Iranian postgraduate students with internal and external locus of control. The students were selected through locus of control questionnaire and it is followed by OSORS questionnaire to measure online metacognitive strategies used by students. The results of study revealed that online metacognitive reading strategies used mostly by internal locus of control students rather than external locus of control students. There were clear interrelationships among types of metacognitive reading strategies used and internal locus of control characteristics. Among three subcategories of metacognitive strategies, students with internal locus of control are more interested to use global strategies, whereas students with external locus of control tend less to use this strategy. Also, there was no significant difference in using problem-solving and supportive strategies used by the students.