["\nAbstract\nThe United States is 25 years into a large‐scale drug overdose epidemic, yet its consequences for gender differences remain largely unexplored. This study finds that drug overdose mortality increased seven‐ and fivefold for men and women, respectively; accounts for 0.8‐year (men) and 0.4‐year (women) deficits in life expectancy at birth in 2017; and has made an increasing contribution (from 1 percent to 17 percent) to women's life expectancy advantage at the prime adult ages between 1990 and 2017. I document a distinctive cyclicality to sex differences in drug overdose. During the epidemic's early stages—the heyday of prescription opioids—gender differences narrowed, but once the epidemic transitioned to illicit drugs in 2010, gender differences widened again. This pattern holds across racial/ethnic groups, and in fact may be even stronger among Hispanics and non‐Hispanic blacks than among non‐Hispanic whites. That we observe this gender dynamic across racial/ethnic groups is surprising since very different trends in drug overdose mortality have been observed for whites versus other groups. The contemporary epidemic is a case of dynamic change in gender differences, and the differential mortality risks experienced by men and women reflect gendered social norms, attitudes toward risk, and patterns of diffusion.\n", "Population and Development Review, Volume 46, Issue 3, Page 443-470, September 2020. "]