A national sample of 295 transgender adults and their nontransgender siblings were surveyed about demographics, perceptions of social support, and violence, harassment, and discrimination. Transwomen were older than the other 4 groups. Transwomen, transmen, and genderqueers were more highly educated than nontransgender sisters and nontransgender brothers, but did not have a corresponding higher income. Other demographic differences between groups were found in religion, geographic mobility, relationship status, and sexual orientation. Transgender people were more likely to experience harassment and discrimination than nontransgender sisters and nontransgender brothers. All transgender people perceived less social support from family than nontransgender sisters. This is the first study to compare trans people to nontrans siblings as a comparison group.