Greg

, a short form of Gregory/Grigory.It appears several times in Doctor Who universe and the relevant 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 (The Gallifrey Chronicles) (EDA: The Gallifrey Chronicles)
 * Greg (Meat) (TW: Meat)
 * Pope Gregory IX (EDA: The Banquo Legacy)
 * Greg (The Runaway Train) (NSA: The Runaway Train)
 * Greg (Storm Harvest) (PDA: Storm Harvest)
 * Father Gregory (Tsar Wars) (AG: Tsar Wars)
 * Grigory (Revelation of the Daleks) (DW: Revelation of the Daleks)

As first name

 * Greg Bishop (TWN: The Twilight Streets, In the Shadows)
 * Greg Blakeman (SJA: Revenge oft he Slitheen)
 * Grigoriy Bugayev (EDA: Emotional Chemistry)
 * Greg Randall (TWA: Everyone Says Hello)
 * Greg Sutton (DW: Inferno)

As last name

 * Mark Gregory (DW: The Invasion)

Featured

 * Gregory Ferguson, who played a young Clem McDonald 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 who 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.