Marc

 occurs several times in the Doctor Who universe and the relevant real world. They are listed below in alphabetical order by surname. If no surname is available, alphabetisation occurs by the disambiguation term — that is, the bit between the parentheses in a title like Waitress (Vincent and the Doctor).

As only name

 * Marcipor, also known as Marc (AUDIO: Tartarus, etc.)

As first name

 * Marc Cory (TV: Mission to the Unknown)
 * Marc Forest (PROSE: The Outlaw Planet)

Behind the scenes

 * Marc Platt