Recent advances in policy development and professional practice in the field of early learning and child care have led to the expectation that it is appropriate and advantageous to include children with disabilities and extra support needs in early child care and learning programs. Yet, to date, evidence-based research on the effects of experiences in inclusive programs has been hampered by the lack of appropriate measures to assess inclusion quality that are reliable, valid, and relatively easy to administer. The purpose of the current study was to examine a newer measure, the SpeciaLink Early Childhood Inclusion Quality Scale (SECIQS), using data from 588 classrooms in child care centres and preschool programs across Canada. Through examination of inter-item consistency and reliability, along with exploratory and confirmatory factor analyses, evidence is provided for the utility and reliability of the measure. In addition, the validity of using both subscales is supported. Implications for policy and practice include recommending the use of all items in the SECIQS and scoring for all three factors in research studies. Further, separate subscale scores for the Inclusion Principles and Inclusion Practices subscales are recommended as useful for centre assessments, quality improvement initiatives, and for educating the field about the contributors to inclusion effectiveness.