Lower perceived risk is a well-established risk factor for initiating substance use behaviors and an integral component of many health behavior theories. Established literature has shown that many substance use behaviors are more prevalent among individuals who identify as lesbian, gay, or bisexual than among those who identify as heterosexual. However, potential differences in perceived risk by sexual identity among individuals with no lifetime use have not been well characterized to date.Data on 111,785 adults aged 18-34 years (including 11,377 lesbian, gay, and bisexual adults) were from the 2015-2019 National Survey on Drug Use and Health. Perceived risks (classified as great risk versus less than great risk) were assessed with 11 National Survey on Drug Use and Health survey items regarding 6 different substances (alcohol, cigarettes, marijuana, cocaine, lysergic acid diethylamide, and heroin). Survey-weighted and sex-stratified logistic regression models were used to estimate sexual identity differences regarding perceived great risk among those reporting no lifetime use. Analyses were conducted in 2021-2022.Gay men, bisexual men, lesbian/gay women, and bisexual women were all significantly less likely than heterosexual peers to perceive great risk associated with specific marijuana, cocaine, lysergic acid diethylamide, and heroin use behaviors. Bisexual men and women were also significantly less likely than heterosexual peers to perceive great risk associated with binge drinking behaviors and smoking ≥1 packs of cigarettes daily.This novel investigation among never users provides evidence that lesbian, gay, and bisexual adults perceive significantly lower risks associated with multiple substance use behaviors than heterosexual adults, which may indicate important sexual identity differences in susceptibility to substance use initiation.