BACKGROUND: Sexual orientation refers to a persons enduring emotional, romantic, or sexual attractions to other people. Sexual orientation measures do not typically consider desires for, or sexual behavior with, transgender people. We describe measures inclusive of transgender people and characterize sexual orientation identity, behavior, and attraction in a representative sample of the U.S. transgender population. METHODS: Between April 2016-December 2018, a U.S. national probability sample of transgender (n = 274) and cisgender (n = 1,162) adults were invited to complete a self-administered web or mailed paper survey. We assessed sexual identity with updated response options inclusive of recent identity terms (e.g., queer), and revised sexual behavior and attraction measures that included transgender people. Multiple response options were allowed for sexual behavior and attraction. Weighted descriptive statistics and sexual orientation differences by gender identity groups were estimated using age-adjusted comparisons. RESULTS: Compared to the cisgender population, the transgender population was more likely to identify as a sexual minority and have heterogeneity in sexual orientation, behavior, and attraction. In the transgender population, the most frequently endorsed sexual orientation identities were bisexual (18.9%), queer (18.1%), and straight (17.6%). Sexually active transgender respondents reported diverse partners in the prior 5 years: 52.6% cisgender women (CW), 42.7% cisgender men (CM), 16.9% transgender women (TW), and 19.5% transgender men (TM); 27.7% did not have sex in the past 5 years. Overall, 73.6% were somewhat/ very attracted to CW, 58.3% CM, 56.8% TW, 52.4% TM, 59.9% genderqueer/nonbinary-females-at-birth, 51.9% genderqueer/nonbinary-males-at-birth. Sexual orientation identity, behavior, and attraction significantly differed by gender identity for TW, TM, and nonbinary participants (all p < 0.05). CONCLUSIONS: Inclusive measures of sexual orientation captured diverse sexual identities, partner genders, and desires. Future research is needed to cognitively test and validate these measures, especially with cisgender respondents, and to assess the relation of sexual orientation and health for transgender people.