Lung cancer incidence is decreasing worldwide among men but rising among women due to recent changes in smoking patterns in both sexes. In Europe, the smoking epidemic has evolved different rates and times, and policy responses to it, vary substantially between countries. Differences in smoking prevalence are much more evident among European women reflecting the heterogeneity in cancer incidence rates. Other factors rather than smoking and linked to sex may increase women's susceptibility to lung cancer, such as genetic predisposition, exposure to sex hormones and molecular features, all of them linked to epidemiologic and clinical characteristics of lung cancer in women. However, biological bases of sex-specific differences are controversial and need further evaluation. This review focuses on the epidemiology and outcome concerning non-small cell lung cancer in women, with emphasis given to the Spanish population.