Multilingualism, as a pervasive phenomenon in the world, is believed to influence language learning process and assist language learners to effectively learn additional language(s). This phenomenon may also exert some effects on the level of affective factors experienced by learners while performing language-related activities. The importance of multilingualism may become more prominent in multilingual societies such as Iran. Accordingly, considering the vital role previous linguistic experience may play in learning additional languages, the current work aimed at investigating the possible effect of multilingualism on reading anxiety of Iranian EFL learners. This book includes five chapters which present an introduction to the work, review of the related literature, method of the study, results and discussion, and conclusions and implications. The findings of the work are further discussed in relation to effective EFL instruction especially to multilinguals.