This article reports on a study that examined the effects of integrating corpus and contextualized lexicogrammar in foreign and second language teaching. The study was conducted in English as a foreign language (EFL) and English as a second language (ESL) courses at 1 Chinese university and 2 U.S. universities, involving 244 participants (236 EFL/ESL students and 8 instructors). A variety of data was collected, including students' corpus search projects and reflection papers, teachers' lesson plans and teaching journals, and a poststudy assessment survey. A close analysis of the data reveals several positive effects of the approach, such as improved command of lexicogrammar, increased critical understanding of grammar, and enhanced discovery learning skills. It also reveals some challenges of corpus-based lexicogrammar learning, including the daunting difficulty many students feel in corpus analysis. The study also identifies some variables influencing learners' experience in using the approach, such as course content, student learning styles, and learning settings. Implications for pedagogy and further research are also discussed.WITH NEW UNDERSTANDINGS ABOUT grammar arising from linguistics and applied linguistics and with the rapid advancement of educational technology, novel theories and teaching practices for grammar instruction have been proposed, including teaching grammar in discourse contexts, approaching grammar from a lexicogrammatical perspective, and using corpus data-driven learning. So far, however, there has been little empirical research on the effectiveness of these new theories and practices.