A web concordancer, a relatively new learning tool for foreign language learning, allows learns to search for occurrences of any lexical term in a corpus. Concordance-based language learning encourages inductive thinking and discovery learning. This study aims to investigate the feasibility of incorporating concordancing into the regular EFL senior high school English curriculum, to examine whether learners' vocabulary level and preferred English learning style (induction or deduction) influence the effectiveness of concordancing on English vocabulary learning, and to elicit learners' feedback on web concordancing. Forty-six second-year senior high school students from an intact class participated in the study. Ten concordancing sessions were incorporated into regular English classes and students worked on the concordancing tasks individually during theses sessions. A pretest, a quiz and a posttest were conducted to measure the students' vocabulary learning. An error correction exercise was also used to gain more understanding about the individual use of the web concordancer. A background questionnaire and an evaluation questionnaire were used to gather students' perceptions before and after the study. The results of the study suggest that concordancing can be an effective tool for language learning. In particular, students of the low vocabulary level group and the induction group benefited more from concordancing. Given careful planning and appropriate guidance, concordancing can be incorporated into secondary level language instruction to benefit language learners.