This experimental study was intended to raise learner autonomy among Iranian native speakers of Persian in their L2 (English) and L3 (Arabic) reading comprehension through cognitive and metacognitive reading strategies instruction (CMRSI). The subjects of the study were divided into intermediate and advanced English language proficiency levels and then put into control and experimental groups. The experimental group was given the treatment (CMRSI) but the control group received the regular classroom materials. The data collected showed that through CMRSI in L2 the reading ability of students in L2 increased. Students could also transfer their strategic reading ability in L2 to L3 reading tasks and as a result improve their L3 reading performance independently without receiving any CMRSI in L3. It is concluded that in order to have readers who are autonomous in reading, and by extension, in other areas of language learning, within a language and across languages we should familiarize students with strategic reading and learning. (Contains 5 tables.)