Existing research suggests that patterns of both men and women serial killers are hyper-gendered. In American society, however, gender norms for women have dramatically changed over time. This study proposes that the patterns of women serial killers reflect the femininity ideals of the time period in which they operated in. The shifts in gender norms are operationalized by three time periods representative of the waves of feminism. The Radford/Florida Gulf Coast University’s serial killer database is used to establish a sample of 1,321 serial killers. Using multivariate regression analyses and controlling for age of last kill, which could potentially alter the kill method but be unrelated to gender, women serial killers do appear to be impacted by the femininity ideals of their time period but not as clearly as initially anticipated. Men serial killers were also found to be affected by changes in femininity ideals. Both women and men serial killers had more feminine kill patterns during the first wave of feminism, but men serial killers had a very violent, hyper-masculine peak during the second wave of feminism that women serial killers did not have.