The purpose of this research was to analyze the mediating effects of the user-provider relationship in light of the effects of physical environment of facilities and service providers’ perception of challenging behavior on the communication between service providers and people with developmental disabilities and challenging behavior. The results indicated the quality of communication increased as the physical environment improved, whereas service providers’ perception of challenging behavior did not directly affect the communication. Meanwhile, the quality of communication increased with the affinity between service providers and users. Also, the relationship between service providers and users mediated between the physical environment, service providers’ perception of challenging behavior and communication. In that this study attempted to establish the effects of the relevant variables on the communication between service providers and people with developmental disabilities and challenging behavior, and the structural relationship among the variables, the findings should be noted as the reference data for further studies.