Greg

, a short form of Gregory/Grigory, has several meanings 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

 * Greg (TW: Meat)
 * Greg (PDA: Storm Harvest)
 * Greg (EDA: The Gallifrey Chronicles)
 * Greg (NSA: The Runaway Train)
 * Father Gregory (AG: Tsar Wars)
 * Grigory (DW: Revelation of the Daleks)
 * Grigoriy Bugayev (EDA: Emotional Chemistry)

As first name

 * Greg Bishop (TWN: The Twilight Streets, In the Shadows)
 * Greg Blakeman (SJA: The Day of the Clown)
 * Greg Randall (TWA: Everyone Says Hello)
 * Greg Sutton (DW: Inferno)

Featured

 * Gregory Ferguson, who played a young Clem MacDonald in TW: Children of Earth: Day One. Children of Earth: Day Three and Children of Earth: Day Four.

Monster specialists

 * Gregory de Polnay, who played D84 in DW: The Robots of Death.

Extra

 * Greg Powell, a professional stunt performer and played a knight in DW: The Time Monster.
 * Gregory Pickup, who played the Tall Man Sleeper in K9TV: Dream-Eaters.

Vocal

 * Greg Donaldson, a voice actor for Big Finish Productions.

As surname

 * Ceri Ann Gregory, who played Trina in TW: Something Borrowed.
 * Nigel Gregory, who played Vince Wilson in K9TV: A Girl's Best Friend.
 * Sara Lloyd Gregory, who played Carys Fletcher in TW: Day One.

Producers

 * Greg Walters, a Story Producer for K9.
 * Gregory Melton, a production designer for Torchwood: Miracle Day.

Visual effects

 * Greg Nicotero, a professional special make-up effects artist for Torchwood: Miracle Day.
 * Greg Spencer, a 2D artist for Doctor Who.
 * Cat Gregory, an assistant editor and a visual effects editor for Doctor Who.

Prose

 * Ian Gregory, who wrote The Best Holiday Ever for Iris: Abroad.

Audio

 * Chris Gregory, who provided the CGI for the cover art of several Big Finish Doctor Who audio stories.