Theodore may refer to:

• Theodore, Australian Capital Territory, Australia
• Theodore, Queensland, Australia
• Theodore, Saskatchewan, Canada
• Theodore, Alabama, United States
• Theodore Reservoir, in Saskatchewan

• Theodore (given name), including a list of people with the name
  • Theodore Roosevelt, 26th President of the United States
• Theodore (surname), including a list of people with the name

• T-Bag (Prison Break) (Theodore Bagwell), in Prison Break
• T-Dog (The Walking Dead) (Theodore Douglas), in The Walking Dead
• Theodore Huxtable, in The Cosby Show
• Theodore, in Alvin and the Chipmunks
• Theodore Grambell, or CatNap, in video game Poppy Playtime
• Theodore "The Roach" Roachmont, from Supernoobs

• Theodore (horse), a British Thoroughbred racehorse
• Theodore Racing, a Formula One constructor

• Theodoros, or Theodorus
• Principality of Theodoro, a former principality in Crimea
• Thoros (disambiguation), Armenian for Theodore