Given that systems thinking is a useful methodology in organization learning, the main purpose of this study was to identify and evaluate how and in what ways we could use systems thinking on curriculum/instruction planning in schools. In this study, we used ethnographic methods of observation and in-depth interviewing to gather information. The study took place in six public elementary schools. The evaluation was focused on the following questions: (a) What happened when the model were used?, (b) What did participants think about using the model in planning and instruction? and (d) In what ways did the use of the model influenced professional development? Evaluation data was collected from three primary sources: (a) principalsí and administratorsí interview (b) teachersí curriculum, lesson plans, interview, and responses to an attitude survey; and (c) researchersí observational notes. Conclusions made based on the results of this study. First, systems thinking can increase the quality of administrator-teacher and teacher-teacher interaction, teachersí curriculum/instruction planning, continuous assessment of curriculum/instruction, and immediate and formative feedback. Secondly, it can also decrease overall time required on task of curriculum/instruction designing in the long run. Consequently, it promises curriculum/instruction design with more accountable quality.