The purpose of this study was to develop and validate an observation measure designed to assess classroom quality in inclusive preschool programs, the Inclusive Classroom Profile (ICP). Developing the rating scale entailed systematic fieldwork in inclusive settings and review of the literature on preschool inclusion. Results from the validation study showed that the measure has good inter-rater agreement, is internally consistent, and shows a good factor structure. Correlations with other measures of classroom quality provided initial evidence for construct validity. This paper argues that traditional measures used to assess quality in early childhood classrooms are useful but may not be sufficient in capturing dimensions of quality that pertain particularly to the support for children with disabilities included in preschool programs. (Contains 5 tables and 1 figure.)