This paper reports on a comparative study exploring Iranian high-school students’ beliefs about learning English and Arabic. Horwitz’s (1987) Beliefs about Language Learning Inventory (BALLI) was used to collect data from 540 high-school students. One-way multivariate analysis of variance was conducted to analyze the data. The MANOVA results revealed significant differences (F (5, 533) = 47.72, P =.000) between students’ beliefs about learning English and Arabic in four categories of the BALLI: foreign language aptitude, the nature of language learning, learning and communication strategies, and motivation and expectations. Students’ beliefs about the difficulty of learning English and Arabic were not significantly different. The findings might be influential in developing and designing more effective language teaching programs in high-school context.