Mr. Smith may refer to:
- Landlord of Professor Longnecker's apartment. [Portrayed by Bill Erwin, Episode #73: "The Mysterious Dr. T". Note that although this name appears in the credits it is not used in the episode itself.]
- Cover name used by Siegfried when he buys the farm across the way from that of 99's Mother in Idaho [Episode #88: "Snoopy Smart Vs. The Red Baron"].