Background: Despite its association with patient safety, few studies on missed nursing care have been conducted in nursing homes. We aimed to describe individual and environmental factors in a sample of registered nurses (RNs) reporting missed nursing care in nursing homes, and to explore the association between these factors and missed nursing care. Methods: In the present, multicentre cross-sectional study, 217 RNs from 43 nursing homes in Northern Italy reported all episodes of missed nursing care (ie, any aspect of required care that was omitted or delayed) that occurred in the 20 most dependent residents (according to RNs’ judgement; 860 residents in total) over 3 consecutive days. Multilevel multivariable logistic regression models were used to test possible explanatory factors of missed nursing care (individual, work-related, organisational, and work environment factors), which were entered in a step-wise manner. Results: Younger RNs (P=.026), freelance RNs (P=.046), RNs with a permanent contract (P=.035), and those working in publicly-owned nursing homes reported more episodes of missed nursing care (P<.012). Public ownership (odds ratio [OR]=9.88; 95% CI 2.22–44.03; P=.003), a higher proportion of residents with severe clinical conditions (OR=2.45; 95% CI 1.12–5.37; P=.025), a lower proportion of RNs (OR=2.24; 95% CI 1.10–4.54; P=.026), and perceived lack of time to care for residents (OR=2.33; 95% CI 1.04–5.26; P=.041) were statistically significantly associated with missed nursing care. Conclusion: Factors associated with missed nursing care are similar in hospitals and nursing homes, and include heavy workload and perceived lack of time for care. Because missed nursing care in nursing homes represents tasks performed specifically by RNs, missed nursing care in this setting should be measured in terms of these tasks. An optimal skill mix is crucial to guarantee not only comfort and basic care for nursing home residents, but also good outcomes for residents with severe clinical conditions.