Background. Approximately 40 percent of individuals using out-of-network physicians experience involuntary out-of-network care, leading to unexpected and sometimes burdensome financial charges. Despite its prevalence, research on patient experiences with involuntary out-of-network care is limited. Greater understanding of patient experiences may inform policy solutions to address this issue. Objective. To characterize the experiences of patients who encountered involuntary out-of-network physician charges. Methods. Qualitative study using 26 in-depth telephone interviews with a semi-structured interview guide. Participants were a purposeful sample of privately insured adults from across the United States who experienced involuntary out-of-network care. They were diverse with regard to income level, education, and health status. Recurrent themes were generated using the constant comparison method of data analysis by a multidisciplinary team. Results. Four themes characterize the perspective of individuals who experienced involuntary out-of-network physician charges: (1) responsibilities and mechanisms for determining network participation are not transparent; (2) physician procedures for billing and disclosure of physician out-of-network status are inconsistent; (3) serious illness requiring emergency care or hospitalization precludes ability to choose a physician or confirm network participation; and (4) resources for mediation of involuntary charges once they occur are not available. Conclusions. Our data reveal that patient education may not be sufficient to reduce the prevalence and financial burden of involuntary out-of-network care. Participants described experiencing involuntary out-of-network health care charges due to systemlevel failures. As policy makers seek solutions, our findings suggest several potential areas of further consideration such as standardization of processes to disclose that a physician is out-of-network, holding patients harmless not only for out-of-network emergency room care but also for non-elective hospitalization, and designation of a mediator for involuntary charges.