Karl

 has several occurrences pertinent to the Doctor Who universe and the real world. They are listed below in alphabetical order by surname. If no surname is available, alphabetization occurs by the disambiguation term — that is, the bit between the parentheses in a title like Waitress (Random Shoes).

As only name

 * Karl (TV: State of Decay)
 * Karl (TV: Silver Nemesis)
 * Karl (AUDIO: The Ultimate Adventure)
 * Karl (PROSE: The Sontaran Games)
 * Karl (AUDIO: The Root of All Evil)
 * Karl (COMIC: The Lodger)

As first name

 * Karl Csokor (PROSE: Another Girl, Another Planet)
 * Karl Dam (PROSE: Parallel 59)
 * Karl Donimo (PROSE: Dry Pilgrimage)
 * Karl Hendryk (AUDIO: The Mutant Phase)
 * Karl Sadeghi (PROSE: The Year of Intelligent Tigers)
 * Karl Taylor (PROSE: The Indestructible Man)

Guest

 * Karl Collins, who played Sean Temple in TV: The End of Time.

Featured

 * Karol Hagar, who played the secretary in TV: Frontier in Space.
 * Karol Keyes (Luan Peters), who played Chicki in TV: The Macra Terror and Sheila in TV: Frontier in Space.

Directors

 * Karl Zwicky, who directed several episodes of K9.

Other

 * Russ Karel, an assistant floor manager for the Season 12 Doctor Who television stories The Ark in Space, The Sontaran Experiment, and Revenge of the Cybermen.