This paper discusses one of the most controversial issues in English language teaching, namely, the use of L1, in this case, Arabic, in teaching English as a foreign language. It first reviews the role of Ll in some major language teaching methods. The paper then presents the rationale for using L 1 in English language teaching. This includes motivation, psychological effects, and the influence of L1 on second language acquisition. The paper concludes by presenting empirical evidence from a field study conducted by Tushyeh (1990) in which Arab teachers of English indicate the extent to which they use L 1, Arabic, in teaching English as a foreign language.