Almost all of the clinical and empirical literature on female parricide victims focuses on mothers killed, with only little information available on stepmothers murdered. This study is the first to compare the victim, offender, and case correlates in incidents when mothers and stepmothers were killed. Supplementary Homicide Report Data for 1976–2007 were used to investigate similarities and differences between the two female victim types in the United States. Similarities between stepmothers and mothers included that more than 70% were White and killed in single victim, single offender incidents. Their killers were adult sons in between 67% and 87% of incidents. Several significant differences emerged with respect to age, involvement in multiple offender incidents, and weapon use. Stepmothers and their stepchildren, relative to mothers and their offspring, were significantly younger. Sixty-four percent of stepchildren, compared with 35% of biological children, were under age 25 at the time of their arrest for murder. A higher percentage of juveniles than adult killers was involved in multiple offender (MO) incidents involving mothers. Relative to their male counterparts, higher percentages of female juveniles were involved in MO incidents involving the deaths of mothers and stepmothers. A higher proportion of female adults, relative to their male counterparts, were involved in MO matricide incidents. Offenders who killed stepmothers, relative to those who killed mothers, were significantly more likely to use guns. Juvenile matricide offenders were significantly more likely to use firearms than their adult counterparts. Possible reasons for the differences are discussed in the conclusion. Copyright © 2013 John Wiley & Sons, Ltd.