Women Veterans may have higher rates of both active and passive tobacco exposure than their civilian counterparts, thereby increasing their risk for lung cancer.To compare differences in active and passive smoking exposure and lung cancer incidence among women Veterans and non-Veterans using prospective data from the Women's Health Initiative (WHI).We used data from the WHI, which collected longitudinal demographic, clinical, and laboratory data on 161,808 postmenopausal women. We employed linear and multinomial regression and generalized linear models to compare active and passive smoking exposure between Veterans and non-Veterans and Cox proportional hazards models to estimate differences in lung cancer incidence rates.After adjustment, Veterans had 2.54 additional pack years of smoking compared with non-Veterans (95% confidence interval [CI] 1.68, 3.40). Veterans also had a 1% increase in risk of any passive smoking exposure (95% CI 1.00, 1.02) and a 9% increase in risk of any workplace exposure (95% CI 1.07, 1.11) compared with non-Veterans. After adjustment for age and smoking exposures, Veterans did not have a higher risk of lung cancer compared with non-Veterans (relative risk = 1.06 95% CI 0.86, 1.30).Women Veterans had higher rates of tobacco use and exposure to passive smoking, which were associated with a higher risk for lung cancer compared with non-Veterans. Clinicians who care for Veterans need to be aware that older women Veterans have more exposures to risk factors for lung cancer.