Rosier is the surname of a wizarding family and can refer to:
- Vinda Rosier, a woman who lived during the 1920s
- Rosier (male), one of the earliest Death Eaters
- Evan Rosier, a later Death Eater and contemporary of the Marauders
- Druella Rosier, wife of Cygnus Black III and mother of Bellatrix, Andromeda, and Narcissa Black
- Felix Rosier — a Slytherin student made Prefect in the 1980s
- Rosier family the surname of a pure-blood wizarding family, and one of the Sacred Twenty-Eight. They are related to the Black, Lestrange and Malfoy families.