Approximately 4.9 million people in the United States have an intellectual or developmental disability (I/DD) (Braddock et al., 2011; Braddock et al., 2015). The life expectancy for people with I/DD has dramatically increased in the last 20 years (Bittles et al., 2002; Emmerich, 2010; Haveman et al., 2010; Margallo-Lana et al., 2007; Patja, Iivanainen, Vesala, Oksanen, & Ruoppila, 2000; Perkins & Moran, 2010; Strydom et al., 2010). Adults with I/DD now live long enough to acquire the same chronic and life-limiting health conditions as the general population, such as cardiovascular disease and cancer (Emmerich, 2010; Friedman, Helm, & Woodman, 2012; Haveman et al., 2011; Patja et al., 2000). While specific chromosomal, genetic, and neurodevelopmental conditions linked to I/DD may also impact aging, often the interactions are not well understood (Janicki, Henderson, & Rubin, 2008). There is evidence to suggest that health care disparities are prominent for adults with I/DD, in particular at the end of life (Havercamp & Scott, 2015; Todd, 2002; Tuffrey-Wijne, 2003). Adults with I/DD face disability specific barriers at the end of life (Friedman et al., 2012; Havercamp & Scott, 2015; Marks, Sisirak, & Hsieh, 2008) including: a lack of accessible medical equipment in health care providers offices and hospitals (Marks et al., 2008); underutilization of palliative care services (Cross, Cameron, Marsh, & Tuffrey-Wijne, 2012; Friedman et al., 2012; Marks et al., 2008; Tuffrey-Wijne, Hogg, & Curfs, 2007); communication difficulties; limited or no health care provider training or experience working with adults with I/DD; residential transitions; and poor pain and symptom management (Bradbury-Jones, Rattray, Jones, & MacGillivray, 2013; Friedman et al., 2012; Hahn & Cadogan, 2011; Ouellette-Kuntz, 2005; Perkins, 2010; Read, 2005; Ryan & McQuillan, 2005; Tuffrey-Wijne & McEnhill, 2008; Webber, Bowers, & Bigby, 2010). As a result, many older adults with I/DD will acquire conditions that go unrecognized, are improperly diagnosed, and are inadequately treated (Haveman et al., 2011; Marks et al., 2008). Although the majority of children and adults with I/DD in the United States live with a family caregiver (Braddock, 2013), many will transition from their family home into a community agency residence as they age (Bigby, 2010; Botsford, 2000; Post, 2002; Todd, 2002, 2005; Wiese, Stancliffe, Balandin, Howarth, & Dew, 2012b). These transitions are often a result of the illness or death of a family caregiver (Braddock et al., 2011; Haley & Perkins, 2004; Jokinen, Janicki, Hogan, & Force, 2012; Merrick & Morad, 2011; Webber et al., 2010). In the United States, the place of residence and funding for older adult services varies by state (Bigby, 2010; Engquist, Johnson, & Johnson, 2012). Adults with I/DD and agency staff often have close relationships and may even refer to one another as family (Ryan, Guerin, Dodd, & McEvoy, 2011b; Todd, 2013). However, agency staff are often unprepared for caring for someone who is at the end of life (Ryan et al., 2011b; Todd, 2005, 2013). Although agency staff report both positive and negative experiences in the literature (Kirkendall, Waldrop, & Moone, 2012; Ryan et al., 2011b; Todd, 2005, 2013; Wiese et al., 2012b), there are numerous issues inherent in end-of-life care that make this experience emotionally and physically challenging (Kingsbury, 2010; Ryan, Guerin, Dodd, & McEvoy, 2011a; Todd, 2005; Todd & Read, 2010). In addition, staff often lack the training and resources to provide end-of-life care (Fahey-McCarthy, McCarron, Connaire, & McCallion, 2009; Ryan et al., 2011a; Ryan, McEvoy, Guerin, & Dodd, 2010; Stein, 2008; Tuffrey-Wijne, Bernal, Hubert, Butler, & Hollins, 2010b). While improvements in end-of-life care for adults with I/DD are needed, the care that these individuals currently receive and the complex experiences of their agency staff caregivers are not well understood (Fahey-McCarthy et al., 2009; Kirkendall et al., 2012; McCallion, McCarron, Fahey-McCarthy, & Connaire, 2012; McCarron, McCallion, Fahey-McCarthy, & Connaire, 2011; Ryan et al., 2011b; Ryan et al., 2010; Stein, 2008; Todd & Read, 2010; Tuffrey-Wijne, Bernal, & Hollins, 2010a; Wiese, Dew, Stancliffe, Howarth, & Balandin, 2012a). This dissertation research will contribute to the literature by exploring where improvements in care are most needed and how to best reduce the inequities in end-of-life care for adults with I/DD and their agency staff caregivers. The long-term goal of this dissertation research is improve the end-of-life care experiences of adults with I/DD and agency staff by better preparing community agencies and health care providers to provide quality end-of-life care to adults with I/DD.