This study examined the impediments a new private secular school with students working at above grade level encountered in it implementation of a project-based curriculum within the context of constructivist theory. Examined were the intended or formal curriculum, its implementation, and effects on the implementation. Data were gathered by observing classrooms, attending board and curriculum committee meetings, and interviewing students, teachers, and parents. The curriculum of the school promised learning that was real, contextual, and engaging. One impediment to forming the curriculum was differing perceptions between parents and board members about its form. Parents also showed concern over differentiation in instruction and wanted their children to receive challenging work. Also, parents who wanted specific subjects emphasized were not realizing the intended goals of integrated learning activities. Systems of structure were imposed on the curriculum, including structure in the physical environment, scheduling of content, time use, and teacher responsibilities. With an open curriculum, the teachers had a greater influence on structure than when it is set by outside goals or standards. The largest discrepancy between intended and implemented curriculum was the dichotomy between project-based, integrated curriculum and academic or subject-based curriculum. An appendix of research records is included. (Contains 13 references.) (JPT)