The proponents of frequent quizzes claim that they stimulate students and have a positive effect on their learning, while the opponents argue that too frequent quizzes might frustrate students and hinder their learning. This study examined the effect of frequent quizzes on Iranian undergraduate English as a Foreign Language (EFL) learners' pronunciation achievement. The nonequivalent group, pretest-posttest design was employed to study two classes of English literature and English teaching students, who were taking the Phonology Course, at Kosar University of Bojnord (KUB) as the experimental group (EG) and control group (CG) respectively. Two 40-item pronunciation tests were developed based on the 3 rd edition of the book Ship or Sheep written by Baker (2006). The reliability of the tests was estimated 0.78 and 0.81 respectively through KR-21 formula. After the pretest administration, both groups were exposed to the same activities; however, only the EG took the quizzes every other session. At the end of the training program, the pretests were rearranged and used as the posttests. The results of the independent samples t-tests from the posttests revealed that the EG had a better performance than the CG suggesting that EFL learners' pronunciation achievement can improve if quizzes are used every other session.