Developing a culture of safety is essential for creating high reliability organizations in health care. Although safety culture can be measured and compared across institutions, the methods organizations should use to improve safety culture have yet to be defined. This systematic review, however, found evidence (and limited evidence at that) to support only two strategies to improve safety culture: executive walk rounds and unit-based safety programs. As many institutions are embarking on efforts to develop safety culture, this review highlights the need for more rigorous evaluation and broader dissemination of such efforts.