A new curricular approach called Entrepreneurs in Action! was developed to encourage development of entrepreneurial thinking, including thinking "outside of a structured setting" and demonstrating creativity in problem solving. The effects of the Entrepreneurs in Action! program on the development of entrepreneurial thinking among elementary, middle, and high school students were evaluated in a study in which 187 students were divided into an experimental group that completed the program (117 students) and a control group (70 students) that did not. Both groups completed pretest/posttest instruments, a demographic survey, and student questionnaire. Data were also collected through a teacher survey and in-class observations. The various data collection instruments were designed to evaluate students' progress in relation to the following categories of entrepreneurial behavior: demonstrates entrepreneurial thinking; considers financial factors; thinks in terms of unifying theme; conducts industry analysis; presents a conception new product/service in a clear, well-developed manner; and considers market research. The study established that, compared with the control group, the experimental group made significant gains on the posttest as a whole and in the key category of entrepreneurial thinking. The types of work products produced by the students in the experimental group exhibited creativity, innovation, and understanding. (Nine tables/figures are included. The bibliography lists 14 references.) (MN)