Introduction This study investigated demographic differences in interpersonal theory of suicide factors and their associations with suicide attempts among sexual minority young adults. Methods 784 sexual minority young adults ages 18–29 (42.7% cisgender men, 42.2% cisgender women, 15.1% transgender/gender diverse; 62.2% non-Hispanic White; 50.5% gay/lesbian, 49.5% bisexual+) completed an online survey assessing lifetime suicide attempts and interpersonal theory of suicide factors. Results Demographic differences included (1) greater perceived burdensomeness among transgender/gender diverse participants compared to other gender groups; (2) greater acquired capability for suicide and suicide attempts among cisgender men compared to cisgender women; (3) greater acquired capability for suicide among bisexual+ compared to gay/lesbian participants; and (4) a lower number of suicide attempts among Asian/Asian American sexual minority participants compared to most other sexual minority participants. All interpersonal theory of suicide factors were significantly associated with a higher number of suicide attempts, though only perceived burdensomeness and acquired capability for suicide remained significant when examining all three simultaneously. No two- or three-way interactions between interpersonal theory of suicide factors were significant. Conclusion The interpersonal theory of suicide may be useful for understanding suicide attempts in this population, with perceived burdensomeness and acquired capability being particularly relevant to consider.