Assessment in special education is a shared practice by a number of professionals. Educational diagnosticians are one such group of licensed professionals who assess students to determine eligibility and service recommendations. This study examined educational diagnosticians' perceptions of their role in fostering home--school collaborations. In particular, we focused on the following: (a) educational diagnosticians' competency to facilitate collaboration, (b) educational diagnosticians' self-efficacy and belief that fostering collaborative efforts between home and school should be done, and (c) educational diagnosticians' perceptions of administrative support of such collaborative efforts. The "Facilitating Home-School Collaboration Questionnaire" (FHSCQ), which was developed by the authors specifically for this study, was completed by a statewide sample of educational diagnosticians and school administrators in a southwestern state. The FHSCQ was found to have good internal reliability and construct validity. Findings are discussed in relation to future research and implications for graduate preparation programs and professional development initiatives to examine, cultivate, and nurture efficacy for collaboration between parents and schools.