since the 1960s the age effects on learning both first and second language have been explored by many linguists and applied linguists (e.g lennerberg, 1967; schachter, 1996; long, 1990) and the existence of critical period for language acquisition was found to be a common ground of all these studies. in spite of some common findings, some issues about the impacts of age on acquiring a second or foreign language are still in controversy. while some believe in the superiority of early beginners to late beginners and the impossibility of acquiring native like proficiency in a second language after the age of puberty, others have opposite ideas. this study was an attempt to investigate the impacts of age on learning reading, writing, and grammar of english as a foreign language in iranian context. to carry out the study, 60 kurdish-persian english language learners in iran language institute of kermanshah were selected and their achievements in reading, writing, and the structure of english language were measured through reading, writing, and grammaticality judgment tests. both descriptive and inferential statistics (t-test) were used to analyze the data of the study. the results indicate that early beginners are better than late-beginners. in fact, age negatively correlates with reading, writing, and grammar learning ability.