"The Doctor is the title character in the long-running BBC science fiction television programme Doctor Who. The character has also been featured in one made-for-television film, and a vast range of spin-off novels, audio dramas and comic strips. In the programme, "the Doctor" is the alias assumed by a centuries-old alien—a Time Lord from the planet Gallifrey—who travels through space and time in the TARDIS, frequently with companions."

Source: Wikipedia

The Doctors (and their actors)

• First Doctor (William Hartnell)
• Second Doctor (Patrick Troughton)
• Third Doctor (Jon Pertwee)
• Fourth Doctor (Tom Baker)
• Fifth Doctor (Peter Davison)
• Sixth Doctor (Colin Baker)
• Seventh Doctor (Sylvester McCoy)
• Eighth Doctor (Paul McGann)
• War Doctor (John Hurt)
• Ninth Doctor (Christopher Eccleston)
• Tenth Doctor (David Tennant)
• Eleventh Doctor (Matt Smith)
• Twelfth Doctor (Peter Capaldi)
• Thirteenth Doctor (Jodie Whittaker)
• Fourteenth Doctor (David Tennant)
• Fifteenth Doctor (Ncuti Gatwa)
• Fugitive Doctor (Jo Martin)