Recent trends in the teaching of English as a Foreign Language (EFL) or English as a Second Language (ESL) have emphasized the importance of promoting thinking as an integral part of English language pedagogy; however, empirical research has not established that training in thinking skills can be combined effectively with EFL/ESL instruction. In this study, the Ennis-Weir Critical Thinking Essay Test was used to assess progress in critical thinking after a year of intensive academic English instruction for 36 Japanese students enrolled in a private two-year women's junior college in Oaska, Japan. A control group received only content-based intensive English instruction, while the treatment group received additional training in critical thinking. The treatment group scored significantly higher on the test ("p" =0.000). The results imply that critical thinking skills can indeed be taught as part of academic EFL/ESL instruction. (Contains 3 tables and 26 references.) (Author/SLD)