Michaelis or Michelis is a surname, and may refer to:
- Adolf Michaelis
- Anthony R. Michaelis, science writer
- Edward Michelis
- Georg Michaelis
- Hans-Thorald Michaelis
- Johann David Michaelis
- John H. Michaelis, American four-star general
- Max Michaelis, South African financier
- Laura Michaelis
- Peter Michaelis
- Leo Michelis
- Leonor Michaelis, known for Michaelis-Menten kinetics
- Sebastien Michaelis, writer of Michaelis' classification of demons
- Paul Charles Michaelis, Bell Labs Scientist