As schools emphasize accountability and academic progress for all students, professional collaboration is a critical aspect of planning accommodations and interventions that address the learning needs of diverse learners. To better understand collaborative processes, the authors investigated the nature of a collaborative planning experience for pairs of special and general education teachers. Teachers were taught the curriculum, rules, instruction, materials, and environment collaboration process (M. A. Prater, 2003) in which teachers compared the demands of the general education classroom with the strengths and limitations of the individual student. Results indicate that sharing common philosophies about educating students with disabilities is an important aspect of successful collaborative planning. Teachers who expressed common philosophies about educating students with disabilities completed the process together. The teachers who did not express similar philosophies completed the process separately. (Contains 2 tables and 1 figure.)