Objective American Indian/Alaska Native (AI/AN) patients are significantly less likely than non‐Hispanic whites to receive guideline‐concordant cancer care. Our objective was to examine cancer treatment decision making among AI/AN patients and their providers. Methods From 2011 to 2014, AI/AN cancer patients and their surgeons were identified through a hospital registry in Washington State. Patients were invited to participate in a mailed survey that queried socio‐demographics, cultural affiliation, everyday perceived discrimination, and trust in providers. Both patients and surgeons were queried about decision‐making quality (collaboration and satisfaction). The primary outcome was association between patient and provider assessments of decision‐making quality. The secondary outcome was non‐adherence to treatment. Results Forty‐nine patients (62% response rate) and 14 surgeons (37% response rate) returned surveys. Half of patients had not completed high school; 41% were living in poverty. Half of patients reported a strong tribal affiliation and most reported experiencing some form of discrimination. Patients endorsed high trust in surgeons and a high quality decision‐making process; and surgeons' rated decision‐making quality even more highly than patients did in every domain. Non‐adherence to treatment recommendations was common (26%) and was significantly associated with lower patient‐reported collaboration and satisfaction with decision making. Conclusions Given the importance of adherence to cancer treatment for survival, the many non‐clinical reasons for non‐adherence, and the currently demonstrated association between decision‐making quality and adherence, it would be worthwhile to investigate how to increase AI/AN patient satisfaction with decision making and whether improving satisfaction yields improved adherence to the cancer treatment plan. Copyright © 2016 The Authors. Psycho‐Oncology Published by John Wiley & Sons Ltd.