BACKGROUND: E-cigarette use behaviors and device and liquid characteristics have addiction, cessation, and health implications. E-cigarettes may exacerbate or reduce existing tobacco and nicotine product disparities by sexual and gender identity. We examine e-cigarette device and liquid characteristics and tobacco and nicotine product use by sexual and gender identity. METHODS: Data are from the VAPER study (wave 5: Feb-Apr 2023), an online cohort of U.S. adults (≥21 years) using e-cigarettes ≥5 days per week. Participants (n=1186) reported on tobacco and nicotine product use and submitted photos of their most used e-cigarette device and liquid. Rao-Scott Chi-square tests with Bonferroni corrections were used to cross-sectionally assess differences in tobacco and nicotine product use behaviors and e-cigarette device and liquid characteristics by sexual and gender identity. RESULTS: A greater percentage of bisexual women vs. heterosexual and gay men used disposable devices (54% vs. 31% and 19%) and nicotine concentrations ≥20 mg/mL (77% vs 59% and 34%). A higher proportion of heterosexual women than men used disposable devices (42% vs 31%). A greater percentage of bisexual (20%) than heterosexual (9%) women never smoked cigarettes (p<
0.05). A higher proportion of heterosexual (9.4%) and bisexual (16.4%) men vs. heterosexual women (3%) used nicotine pouches (p<
0.05). CONCLUSIONS: E-cigarette characteristics, which have implications for addiction, health, and cessation, and tobacco and nicotine product use behaviors vary by sexual and gender identity. Targeted interventions may be needed to alleviate and prevent health disparities. Agencies must consider potential variation in regulatory impacts by sexual and gender identity. IMPLICATIONS: This study of adults frequently using e-cigarettes highlights differences in e-cigarette device and liquid characteristics and tobacco and nicotine product use by sexual and gender identity. For example, a greater percentage of bisexual and heterosexual women than heterosexual men used disposable e-cigarette devices. Given the variation in how e-cigarettes and other tobacco and nicotine products are used, researchers and regulators must consider how health outcomes, cessation behaviors, and responses to interventions or regulatory actions associated with e-cigarette use may vary by sexual and gender identity. .