Again, organizational culture matters. Why? Culture is comprised of the shared values and norms within a group that can influence decisions made by a person, a team, or a health care system. Changing behavior is hard; and it's especially difficult without paying attention to and addressing culture. This article outlines an action plan for how one might begin to change organizational culture that results in medical overuse.The authors convened a multidisciplinary stakeholder advisory committee, reviewed social science theory and literature, studied both successful and unsuccessful attempts at improving high value care, and interviewed innovators from 23 organizations across the U.S.; and they decided upon four conditions for change that foster collegiality and collaboration across providers, providers and patients, and healthcare system leaders.