Objectives: Intimate partner femicide (IPF) is a public health issue with far-reaching and extreme consequences. As previous research mainly has treated IPF as an adult phenomenon, young victims of such violence have been rendered invisible . Consequently, youth IPF is not well understood and little is known about factors specific to IPF against adolescent and young adult females. Purpose: The aim of this study is to examine factors related to youth IPF (≤ 25 years) and to compare cases of youth IPF with cases of adult IPF (≥ 26 years) regarding these factors. Victim and perpetrator characteristics are explored, as well as factors related to the relationship and circumstances of the crimes. Methods: This epidemiological study is based on a national dataset that involves all homicides in Sweden between 1990 and 2017. Incidents of male-perpetrated femicide in which the perpetrator and victim were or had been in an intimate relationship were analyzed. Descriptive and multivariate analyses with odds ratios (OR) were conducted in order to make group comparisons between young (n = 62) and adult (n = 320) IPF. Results: Our study reveals interesting differences between youth and adult IPF, in which youth IPF is more likely to be motivated by relationship break-up, involve strangulation of the victim and drug use. Conclusions: Our study sheds light on the factors and circumstances that play an important role in youth IPF, and could be fruitful to target in future prevention and intervention efforts that aim to combat severe violence against adolescent and young adult females.