BACKGROUND: Characterising sexual networks with transmission of sexually transmitted infections might allow identification of individuals at increased risk of infection. We aimed to investigate sexual mixing in Neisseria gonorrhoeae transmission networks between women, heterosexual men, and men who report sex with men (MSM), and between people with and without HIV. METHODS: In this cross-sectional observational study, we whole-genome sequenced N gonorrhoeae isolates from the archive of the Gonococcal Resistance to Antimicrobials Surveillance Programme (GRASP).w Isolates that varied by five single nucleotide polymorphisms or fewer were grouped into clusters that represented sexual networks with N gonorrhoeae transmission. Clusters were described by gender, sexual risk group, and HIV status. FINDINGS: We sequenced 1277 N gonorrhoeae isolates with linked clinical and sociodemographic data that were collected in five clinics in England during 2013-16 (July 1 to Sept 30 in 2013-15; July 1 to Sept 9 in 2016). The isolates grouped into 213 clusters. 30 (14%) clusters contained isolates from heterosexual men and MSM but no women and three (1%) clusters contained isolates from only women and MSM. 146 (69%) clusters comprised solely people with negative or unknown HIV status and seven (3%) comprised only HIV-positive people. 60 (28%) clusters comprised MSM with positive and negative or unknown HIV status. INTERPRETATION: N gonorrhoeae molecular data can provide information indicating risk of HIV or other sexually transmitted infections for some individuals for whom such risk might not be known from clinical history. These findings have implications for sexual health care, including offering testing, prevention advice, and preventive treatment, such as HIV pre-exposure prophylaxis. FUNDING: National Institute for Health Research Health Protection Research Unit; Wellcome; Public Health England.