The study was proposed to find out the effect of frequent testing on students' academic achievement at undergraduate level. In this study, quasi-experimental pretest post-test control group design was used. Two intact groups, control (28) and experimental (51) were selected that were undergone a Research Methods course at undergraduate level. Two instruments were used for data collection; achievement test and weekly tests. Achievement test was developed as a research tool for both control group and experimental group. The achievement test and weekly tests were developed by the researchers and comprised of multiple-choice questions and descriptive questions. The validity of instrument was ensured by opinions of experts who were teaching the course. In the intervention, the experimental group was assessed by frequent testing and the control group was assessed by traditional testing. Experimental group was tested on weekly basis. Including midterm and final term total of 14 tests were administered on weekly basis only to the experimental group and for the control group, only midterm and final term tests were administered. Both groups were compared on the scores of achievement test. The result revealed the statistically significant difference between the achievement scores of control group and experimental group with Cohen's large effect size (d=1.67) in the post-test mean scores. The results showed that the frequent testing affect the students' academic achievement. Hence it is recommended for teachers and higher education institutions that they may include frequent testing in educational teaching courses for their prospective teachers.