© 2020 Elsevier Inc. Introduction: Oncologists have increasingly been proponents of shared decision making (SDM) to enhance patient outcomes and reduce unnecessary health care spending. However, its effect on patient out-of-pocket costs is unknown. This study investigated the relationship between patient preferences for SDM and financial toxicity (FT) in patients with metastatic breast cancer (MBC). Patients and Methods: This cross-sectional study utilized surveys of women aged ≥ 18 with MBC who received care at two academic hospitals in Alabama from 2017 to 2019. Patients self-reported their SDM preference (Control Preferences Scale) and FT (Comprehensive Score for Financial Toxicity [COST] tool; 11-item scale, with lower scores indicating worse FT). Effect sizes were calculated using the proportion of variance explained (R2) or Cramer's V. Differences in FT by SDM preference were estimated using mixed models clustered by site and treating medical oncologist. Results: In 95 women with MBC, 44% preferred SDM, 29% preferred provider-driven decision making, and 27% preferred patient-driven decision making. Patients preferring SDM were more often college educated (53% vs. 39%; V = 0.12) with an income greater than $40,000/y (55% vs. 43%; V = 0.18). Overall median COST was 22 (interquartile range, 16-29). After adjusting for patient demographic and clinical characteristics, patients preferring patient-driven decision making trended toward worse FT (COST 17: 95% confidence interval, 12-22) compared to those preferring SDM (COST 19: 95% confidence interval, 15-23) and those preferring provider-driven decision making (COST 22: 95% confidence interval, 17-27). Conclusion: Patients preferring more patient-driven decision making reported worse FT, although differences did not reach statistical significance. Further research is needed to understand this relationship.