This study investigates English as a second language (ESL) teachers' beliefs in grammar teaching. A 32-item questionnaire was administered to 11 ESL teachers in a language school in California. The results show that the participants generally believe that the formal study of grammar is essential to the eventual mastery of a foreign or second language when language learning is limited to the classroom. Grammar is also generally believed to be best taught explicitly, inductively or deductively, but not implicitly. The teachers tend to value error correction, and they seem to believe that grammar errors should be corrected even when they do not interfere with comprehensibility. It was also found that the teachers generally believe in the negative influence of first language (L1) on second language (L2), but they do not tend to believe in the positive influence of L1 on L2. The teachers also seem to believe that metalanguage should be used for learners of all proficiency levels. Furthermore, they generally believe that practice is of crucial importance to grammar learning. Finally, the teachers believe that their previous training greatly improved their confidence and skills in teaching grammar. Study Questionnaire on ESL Teachers' Beliefs in Teaching Grammar is appended. (Contains 8 tables.)