This paper discusses the change of educational governance by developing and using a theory of policy instrumentality. It is based on the policy instruments approach in political studies and on the cultural-historical activity theory. It is used to study the relationships and changes of policy instruments and objectives of a major school development program in Taiwan launched in 2007. The group in charge of the program evaluated and changed both the objectives and instruments of the program in 2010. The direction of this transformation was from an approach based on competition and control towards an approach that emphasizes school autonomy, quality of curriculum and collaboration and learning between schools. The paper distinguishes three dimensions of policy instruments to analyze how the new orientation became embedded in the instruments used in the program implementation. The paper further suggests that policy learning can be analyzed in terms of remediation, that is, collective redesign of the system of instruments.