Several problems limit our understanding of the ways that gender and sexual orientation influence disordered eating. These include the reliance on measures that have been developed and validated in samples of cisgender heterosexual women, and the lack of confirmed measurement invariance that allows us to meaningfully compare these experiences between groups. This study was an EFA to CFA exploration of the Eating Disorder Examination Questionnaire in a group of heterosexual, bisexual, gay, and lesbian men and women. In total 1638 participants were recruited via adverts in traditional and social media to complete an online survey. A 14-item, three-factor model of the EDE-Q was confirmed as best fitting the data and measurement invariance between groups was ascertained. Sexual orientation influenced disordered eating and muscularity-related thoughts and behaviours in men but not women. Heterosexual men reported more muscularity-related concerns and behaviours, whereas gay men showed more thinness-related concerns and behaviours. Bisexual participants showed a different pattern, highlighting the importance of treating this group individually and not collating all non-heterosexual participants together. Small but significant effects of sexual orientation and gender have an impact on the kinds of disordered eating thoughts and behaviours one might experience, and could influence prevention and treatment. Clinicians may be able to provide more effective and tailored interventions by taking into account gender and sexual orientation in sensitive ways.