The effects of collaborative learning have been well studied in the context of students' developing reading proficiency. However, only a handful of scholars have examined the impact of collaborative learning on students' development of higher order thinking skills (Chapman, Ramondt, and Smiley, 2005; Lehtinen et al., 1999; Ma 2009). This article reports a case study that explored how collaborative learning supports English as a Second Language (ESL) learners' development of higher order thinking skills in a traditional ESL grammar class. To collect data, the researcher employed interviews, audio recordings, and class observations. It is hoped that through understanding this relationship not only will ESL lean1ers develop their higher order thinking skills while acquiring a second language, but also school directors and instructors will be inspired to create effective collaborative learning activities.