Purpose:To examine which characteristics of the practice environment were associated with missed nursing care in U.S. acute care hospital units. Design: A descriptive, correlational study used secondary analysis of the 2015 National Database of Nursing Quality Indicators ® Registered Nurse (RN) Survey data. Subscales of the Practice Environment Scale of the Nursing Work Index were used to measure practice environment characteristics. The sample included 1,583 units in 371 hospitals, containing survey responses from 31,650 RNs. Methods: Multilevel logistic regression was performed to estimate the effects of the practice environment characteristics on missed care, controlling for hospital and unit characteristics. Results: About 84.1% of unit RNs reported missing at least one of the 15 necessary care activities. Good environment units had 63.3% significantly lower odds of having RNs miss care activities than poor environment units. Units had 81.5% lower odds of having RNs miss any necessary activities with 1 point increase of the staffing and resource adequacy score; 21.9% lower odds for 1 point increase in the nurse-physician relations score; and approximately 2.1 times higher odds with 1 point increase in the nurse participation in hospital affairs score. Conclusions: Good environments were significantly associated with lower levels of missed care. The impact on missed care differed by the characteristics of the practice environment. Clinical Relevance: Hospital and nursing administrators should maintain good practice environments for nurses to reduce missed care activities and thus potentially improve patient outcomes. Specifically, their efforts should be targeted on improving staffing and resource adequacy and nurse-physician relations and on reducing workloads on hospital affairs.