This study investigates the relationship between intelligence and foreign language learning in general, and the learning of vocabulary and grammar in particular. It also investigates the effect of extra practice on foreign language learning on learners with equal intelligence. The participants were 182 high school students at grades two and three. They were given Raven’s Progressive Matrices, which is a test of general intelligence, and an achievement test of English based on their EFL textbook at school. The English test consisted of two subparts: vocabulary and grammar. Correlation coefficient was run on intelligence test scores and English test scores. The results showed a weak positive relationship between intelligence and foreign language learning, and learning of vocabulary and grammar. For investigating the effect of practice, some students who attended English classes and some of those who didn’t were chosen in a way that their mean intelligence score was equal. Then their mean English test score was calculated. The mean English test score of the students who attended English classes was significantly higher than those who didn’t. These results suggest that intelligence affects foreign language learning, but extra practice can offset the effect of intelligence. تفاصيل المقالة