Purpose: This study was done to develop an instrument to measure the work environment in nursing homes and to evaluate its psychometric properties. Methods: Instrument development was conducted in three phases: development of the initial questionnaire, content validity and pilot-testing, and construct validity and reliability testing. Participants were 184 nurses from 62 nursing homes in South Korea. Exploratory factor analysis, confirmatory factor analysis, and examination of internal consistency were used to verify the psychometric properties of the instrument. Results: The final model derived from the factor analysis yielded 27 items across five domains: nurses’ participation in nursing home affairs; well-defined scope of practice; nurse managers’ ability, leadership, and support of nurses; staff and resource adequacy; and communication and coordination. The fit indices in the confirmatory factor analysis were acceptable. Total Cronbach’s ⍺ was .93 (sub-domains ranged .77~.88). Conclusion: The results indicate that the selected items are suitable for measuring the work environment of nursing homes in South Korea. This instrument may be useful in nursing home-related research and may be used to improve the health outcomes of older adults in nursing homes.