Increased urinary incontinence is one of the most common changes during menopause. This study aimed to investigate the effect of Nigella sativa L. seed oil on urinary incontinence and quality of life (QoL) (primary outcomes) and sexual function (secondary outcome) in menopausal women. In this triple‐blind randomized controlled trial, 60 women in Tabriz‐Iran were equally allocated into two treatment and control groups using block randomization. The women applied 2–3 drops of Nigella sativa L. seed oil or placebo on their stomachs below the novel twice a day for 8 weeks. The data collection instruments were completed at baseline and just after the intervention. After intervention, the mean rank score of mixed urinary incontinence was significantly lower (p = .04) and the mean score of the incontinence‐QoL was significantly higher (mean difference 12.63, 95% CI 2.33 to 22.93; p = .017) in the treatment group than the control group. However, there were no significant differences in stress incontinence, urge incontinence, sexual function, and menopause‐specific QoL of women between the groups (p > .05). The results indicated the positive effect of the Nigella sativa L. seed oil on mixed incontinence and incontinence‐QoL; nevertheless, to make a certain conclusion, further studies are required.