This study sought to examine (1) the participation of adults with intellectual disabilities in empowerment evaluation of their services plans and (2) the impact of participation in empowerment evaluation on their level of self-determination. A non-equivalent groups design was used with two groups of participants. Only one group participated in an empowerment evaluation intervention. The author collected participation and self-determination measures from participants in the target and comparison groups at pre and post-intervention using mixed methods. The results of the study showed that barriers to participation of adults with intellectual disabilities in the empowerment evaluation of their services plans were lack of an assigned role and lack of accessibility of the process and information. Facilitators of participation in empowerment evaluation were ongoing involvement of adults with intellectual disabilities over time designing accessible information and evaluation processes, and training in conducting evaluation. The outcomes of the intervention included the participation of adults with intellectual disabilities in the target group in the assessment of preferences, goal accomplishment and in the preparation for the meeting. There were no differences in the comparison group regarding participation in empowerment evaluation in the post-intervention when compared to baseline. Similarly, both groups of participants did not participate in decision-making. Self-determination results included more specific self-knowledge and self-awareness of preferences and important things, more specific sense of accomplishment, and identification of staff as a resource to accomplish their goals for adults with intellectual disabilities in the target group. Contextual factors such as regulations for the implementation and evaluation of individual services plans and lack of resources prevented adults with intellectual disabilities from making decisions regarding their services plans. The results of this study revealed the importance of including contextual and environmental factors in addition to individual capacity of adults with intellectual disabilities to make decisions. The findings of this study question current theoretical models of self-determination. A Disability Studies perspective is used to discuss the findings of this study regarding the allocation of power that prevents adults with intellectual disabilities from making decisions that impact their lives.