The study investigated the influence of the humanistic orientation on the perspectives of service providers working with individuals with intellectual and developmental disabilities (IDD) and the self-evaluation of service users. The humanistic orientation, which emerged in the 1990s, emphasizes the rights of people with IDD to lead a meaningful life based on their personal needs and desires. However, challenges persist as some service providers prioritize the acquisition of normative life skills over fostering autonomy. The study was based on quantitative methodology and included 61 service providers and 95 of their service users. The study’s findings indicate that the humanistic orientation was endorsed by nearly one half of the service providers compared with one third who endorsed a medical orientation. Those endorsing a humanistic orientation also reported that their service users had higher levels of efficacy than those with a medical perception of IDD. Positive correlations were found regarding the assessments made by service providers and their service users on self-efficacy. Findings suggest that a humanistic orientation encourages optimism among service providers and a positive dyadic interaction between providers and users. It is suggested that the humanistic orientation be applied as a guiding principle underlying the daily support provided to adults with IDD.