Background: The aim of this study was to evaluate the effects of a training program focusing on improvement of emotional intelligence (EI) and support staffs' awareness of their behaviour towards people with an intellectual disability based on interactional patterns. The support provided regarding the needs for autonomy, relatedness, and competence was observed in line with self-determination theory (SDT). Method: A pre-test/post-test control group design (N = 29) was used, with 17 support staff participating in the experimental group. For both groups, video recordings of interactions between staff and clients were analysed with an SDT-observation system. Results: The results showed that a training program focusing on EI and interactional patterns positively affected the support provided by staff with regard to clients' needs for autonomy, relatedness, and competence. Conclusions: As most EI studies focus on insights and understanding of oneself, this study is an important first step in focusing on staff behaviour during daily interactions.