Aims The aim of the study was to identify the predictors of contracting COVID‐19 among older people in nursing homes in Iran. Design A case–control study. Methods Four‐hundred‐nine nursing home residents aged 60 years and above, with a 1:2 ratio of those infected with SARS‐CoV‐2 to those not infected, from six nursing homes in Tehran between 25 March and 12 July 2021 were recruited. Participants completed a questionnaire comprising demographic and underlying disease questions, practice about prevention principles of SARS‐CoV‐2 infection, probably predisposing factors of the infection, and environmental and staff characteristic of nursing homes. Logistic regression was used to determine risk factors associated with contracting COVID‐19. Results The mean age was 77.37 (±9.20) years; 54% were female. A logistic regression model showed that the most important predictors of becoming infected by SARS‐CoV‐2 included not using mask outside the room (odds ratio [OR]: 3.37, 95% CI: 1.74–6.53), longer staff shifts (OR: 3.02, 95% CI: 1.68–5.43), using cloth mask or not wearing a mask (OR: 2.47, 95% CI: 1.13–5.42) and not having glass barrier in visitors space (OR: 1.95, 95% CI: 1.11–3.50). Conclusion The results indicate that an increase in older people becoming infected by SARS‐CoV‐2 in nursing homes is probably because of not wearing a mask in common places, use of a cloth mask, longer staff shift durations and not having a glass shield when interacting with visitors from outside of nursing homes. Impact The predictors identified in this study can assist in reducing SARS‐CoV‐2 infections in older people institutionalized in nursing homes. These data items can also inform the development of interventions to improve principles of infection prevention and control.