Very little is known about co-offending by female sexual offenders (FSOs), especially in terms of diverse forms of offender groupings. To address this gap in the literature, this study uses 21 years (1992-2012) of National Incident-Based Reporting System data to analyze incidents of sexual offending committed by four female groupings: solo FSOs (n = 29,238), coed pairs consisting of one male and one FSO (n = 11,112), all-female groups (n = 2,669), and multiple perpetrator groups that consist of a combination of three or more FSOs and male sexual offenders (MSOs; n = 4,268). Using a multinomial logistic regression model, the data show significant differences in offender, victim, and crime context incident characteristics. The data also indicate that incidents with solo FSOs and all-female groups have similar characteristics, coed pairs and multiple perpetrator incidents have similar characteristics, and these two categorizations are fairly distinct from one another. Implications of this research are discussed in addition to directions for future research on female sexual offending.