Treatment fidelity is a critical standard within the exploration of evidence-based treatment effectiveness. In order for experimental research studies to meet the rigor of evidence-base scrutiny, researchers are expected to address how and to what degree the experimental treatment was delivered in alignment with standard procedures for that treatment. Although child-centered play therapy (CCPT) can be delivered according to an established protocol, measures for adherence to such protocol have not been developed. The purpose of the current study was to develop a measure to determine adherence to treatment fidelity. Four experienced CCPT therapists reviewed literature and observed play therapy sessions facilitated by other experienced play therapists to confirm the validity of verbal CCPT procedures and establish interrater reliability on the created instrument. Results revealed a free marginal multirater kappa at .82 and an intraclass correlation coefficient (ICC) at .95 indicating strong consistency of raters and interrater reliability among raters for the Child-Centered Play Therapy-Research Integrity Checklist (CCPT-RIC). Additionally, verbal categories with the CCPT-RIC were defined for the purposes of research coding.