The concept of window of entrepreneurship is used in order to explore the relationship between corporate governance and corporate entrepreneurship. Entrepreneurship is a propensity, which can be triggered or terminated through the influence of corporate governance mechanisms. The window of entrepreneurship expresses the temporary character of entrepreneurship, indicating that a firm can open or close the firm for entrepreneurial action. We find indications of the window of entrepreneurship in two riding schools, one governed by a private firm and one governed by an association. The mechanism of the board of directors was found to be conducive for opening the window in the two cases. The mechanism of the product market and the market for managerial labour influenced the closing of the window. Thereby it has been indicated that corporate entrepreneurship is a propensity that can be triggered and terminated.