There are several notable people with the surname Orenstein.
- Alexander Jeremiah Orenstein, South African medical scientist and army general
- Henry Orenstein, American poker player and entrepreneur
- Henry Orenstein (painter), Canadian artist
- Howard Orenstein, American lawyer and politician
- Joan Orenstein, Canadian actress
- Leo Orenstein, Canadian television producer and director
- Peggy Orenstein, American writer
- Toby Orenstein, an American theatrical director, producer, and educator
- Walter Orenstein, American vaccinologist
- Zigu Ornea (born Orenstein or Ornstein), Romanian cultural historian