Children with disabilities have mixed feelings about their inclusion experiences. The purpose of this study was to explore the validity and reliability of results from the Lieberman-Brian Inclusion Rating Scale for Physical Education. Experts in adapted physical education (n = 10) established content and face validity (mean = 4.68 ± 0.56) on a five-point scale through three rounds of evaluation through the Delphi method. Next, elementary physical education teachers (n = 15) and two independent raters established test--retest reliability (r = 0.87, p < 0.001; intra-class correlations (ICC) = 0.93, p < 0.001) and inter-rater reliability (r = 0.69, p < 0.001; ICC = 0.82, p < 0.001) respectively. Physical education teachers among others can use this valid and reliable scale to determine the extent to which teachers attempt to make an environment inclusive. Practical uses for this instrument are program evaluation, intervention research, and as a teaching tool.