BACKGROUND AND OBJECTIVES: Despite increasing attention to the use of shared decision making (SDM) in the emergency department (ED), little is known about ED patients' perspectives regarding this practice. We sought to explore the use of SDM from the perspectives of ED patients, focusing on what affects patients' desired level of involvement and what barriers and facilitators patients find most relevant to their experience. METHODS: We conducted semistructured interviews with a purposive sample of ED patients or their proxies at two sites. An interview guide was developed from existing literature and expert consensus and based on a framework underscoring the importance of both knowledge and power. Interviews were recorded, transcribed, and analyzed in an iterative process by a three-person coding team. Emergent themes were identified, discussed, and organized. RESULTS: Twenty-nine patients and proxies participated. The mean age of participants was 56 years (range, 20 to 89 years), and 13 were female. Participants were diverse in regard to race/ethnicity, education, number of previous ED visits, and presence of chronic conditions. All participants wanted some degree of involvement in decision making. Participants who made statements suggesting high self-efficacy and those who expressed mistrust of the health care system or previous negative experiences wanted a greater degree of involvement. Facilitators to involvement included familiarity with the decision at hand, physicians' good communication skills, and clearly delineated options. Some participants felt that their own relative lack of knowledge, compared to that of the physicians, made their involvement inappropriate or unwanted. Many participants had no expectation for SDM and although they did want involvement when asked explicitly, they were otherwise likely to defer to physicians without discussion. Many did not recognize opportunities for SDM in their clinical care. CONCLUSIONS: This exploration of ED patients' perceptions of SDM suggests that most patients want some degree of involvement in medical decision making but more proactive engagement of patients by clinicians is often needed. Further research should examine these issues in a larger and more representative population.