There are many obstacles to including critical thinking as a learning objective in Introductory Accounting courses. However, the presence of these obstacles does not change the collective conclusion from the accounting profession that critical thinking skills are a prerequisite for a successful accounting career and that accounting educators should assist students in the development of these skills. The purpose of this paper is to present a learning strategy, entitled the Challenge Problem approach, to encourage the development of critical thinking skills in Introductory Accounting courses. Under this approach, the development of critical thinking skills is a primary learning objective of Introductory Accounting courses that is fostered by an active learning environment in the classroom and supported by an experiential learning pedagogy. In addition, critical thinking skills are tested on each exam with a Challenge Problem. This paper presents two examples of Challenge Problems, along with rubrics to evaluate the students' performance. The rubrics identify the strengths and weaknesses in the students' critical thinking abilities and can improve the design of future critical thinking exercises in principles courses.