This study set out to examine the effect of explicit consciousness-raising of autonomous learning activities on a group of students’ General English achievement test scores following a mixed methods design. At the beginning of the study, four intact classes were selected based on their availability, of which one class was assigned to the experimental group and the others to the control groups, through random assignment. The treatment groups received a 10 session treatment on a number of autonomous learning activities to be done outside the classroom after the midterm exam which functioned as the pretest. At the end of the semester and after the treatment, all the four groups took the final exam (the posttest). An independent-samples t-test was conducted to compare the posttest scores for treatment and no-treatment groups, and one-way ANOVA was run followed by Tukey HSD as a follow-up measure to find out the probable differences between the groups. To check the probable significant differences between students’ pretest and posttest scores, a set of paired-samples t-tests was run separately for the experimental group and control group 1. Then, the researchers conducted descriptive analysis related to the questionnaire items and checked the correlation of all the data taken from the tests and the questionnaire items. The results indicated that the treatment significantly led to better test scores in this context, where the eta squared statistic indicated a large effect size. In addition, the semi-structured interview data confirmed the results.