The concept of motivational regulation has always been on the agenda of researchers; however, the role of motivational regulation has received relatively little attention in terms of writing skills. Hence, the present study aims to investigate the potential correlations between motivational writing regulation strategies concerning collaborative writing beliefs of undergraduate L2 writers. To this end, a total of 102 undergraduate L2 writers were surveyed. To collect the data, two research tools were used. The first one is "the Writing Strategies for Self-regulated Learning Questionnaire" ("WSSRLQ") (Teng and Zhang 2016a). This questionnaire conceptualizes motivational writing regulation strategies in terms of cognitive, metacognitive, and social-behavioral factors. The second data collection tool employed in the present study was the "Collaborative Learning Beliefs Survey," which was prepared based on Roskams (1999). According to the findings of the study, there is a correlation between self-regulated writing strategies and collaborative learning beliefs. Hence, it is suggested that EFL writing instructions focus on motivational regulation strategies and other aspects of self-regulated strategies to ensure effective L2 writing instruction.