This study focuses on learners' self-regulation which is one of the essential skills for student achievement in blended courses. Research on learners' self-regulation skills in blended learning environments has gained popularity in recent years however only a few studies investigating the correlation between self-regulation skills and student achievement in blended learning environments exist. Self-regulation is related to self-efficacy, anxiety, interactivity, satisfaction with and usefulness of the system. Self-regulated learners are more likely to accomplish at online learning. In this study, a total of 267 military vocational college students were taught computer programming during a 15-week-long semester in a blended learning context, which involved using both face-to-face teaching and online learning through MOODLE over intranet. Participants were the graduates of vocational high schools and the students at the departments of Computer Technologies and Electronics & Communication Technologies and were all male. Liaw and Huang's Self-Regulation Scale with six subscales was used to collect the data during the last two weeks of instruction. Regression analyses were conducted to analyze the data. The results revealed that self-regulation was affected by perceived anxiety, interactivity in the online learning environment, and perceived self-efficacy. Learners' academic achievement has been affected only by perceived self-efficacy.