The increasing global recognition of many common disease conditions requires population-level rather than individual-level solutions. The purpose of this article was to challenge nurses to shift their thinking from individual health to the health of populations by providing a comprehensive understanding of what population health is; discussing the role nursing plays in improving the health of populations; describing the Conceptual Model of Nursing and Population Health (CMNPH); and identifying implications for population health research methods, nursing education, and nursing practice. The conceptual model is based on our understanding of the meaning and methods of population health and is intended to advance contributions of the discipline of nursing to population health.