Background: Intellectual disability occurs in approximately 7 to 8 million Americans. The literature demonstrates that this population experiences communication barriers and mischaracterization of abilities during health care encounters, raising ethical considerations regarding patient involvement in health care decisions. Yet, there has been limited research on the involvement of those with intellectual disability in health care decision making. This study examined perceptions of adults with intellectual disability related to involvement in health care decisions. Methods: A quantitative survey instrument was distributed to 120 organizations throughout the United States that provide services to individuals with intellectual disability; their participation was sought to share information about the survey with eligible individuals. Survey results were analyzed to determine the extent to which respondents experienced communication barriers, mischaracterization of abilities, and/or exclusion in health care decision making. Results: Nineteen adults aged 18 years or older completed the survey; the majority (63.2%) of respondents were female. A majority (57.9%) did not perceive communication barriers. In addition, most participants (63.2–78.9%) did not report mischaracterization of their abilities based on responses to questions examining this issue. Roughly 58% of participants felt they had control during physician appointments. Nearly half (47.4%) were either unsure or disagreed that they had control over their health care decisions. Discussion: Results of this study suggest communication and mischaracterization issues are present for this population at varying levels. This study also suggests that adults with intellectual disability are largely unsure of their inclusion in health care decisions. Ethical complexities and considerations warrant further research.