Like the Doctor, the renegade Time Lord known as the Master used many aliases. However, while the Doctor used false names on a fairly ad hoc basis to avoid awkward questions, the Master usually adopted them in order to further whatever scheme he was embarked upon at the time.
| Alias | When used | Story | Etymology | |
|---|---|---|---|---|
| Professor Carl Thascalos | to give Jamie McCrimmon the Necronomicon, and to gain access to facilities of the Newton Institute | The Nameless City The Time Monster |
Greek for master, pointed out by Jo Grant | |
| Colonel Masters | to infiltrate Rex Farrel's plastics company | Terror of the Autons | ||
| Emil Keller | assumed identity of the creator of the Keller Machine | The Mind of Evil | Emil is derived from the Latin word aemulus, meaning rival, and Keller is derived from Old English cwellere, meaning executioner | |
| Martin Jurgens | while posing as an Adjudicator | Colony in Space |
Anagram of Master Gunnjir (gunnjir is the spear of Odin, head of the Norse pantheon) | |
| Mr Magister | to insinuate himself socially into the Devil's End community as a vicar | The Dæmons | Latin for master | |
| Frey | whilst in Sweden, 141 | The Spear of Destiny | Old Norse for master | |
| Inspector LeMaitre | to infiltrate a village fete by pretending to be a police inspector from Scotland Yard | Last of the Gaderene | French for the master | |
| Duke Dominus | to impersonate a 1930s Chicago gangster | The Duke of Dominoes | Dominus from the Latin for lord or master of the house | |
| Professor Dominus | Doorway to Hell | Spanish for dominate | ||
| Estro | while posing as an adviser to Lord Haldoran in an effort to procure a Dalek matter transmuter | Legacy of the Daleks | Esperanto for master | |
| Dr Damien Scott | Whilst working for the Dominus Institute in the body of a future incarnation. | Vampire of the Mind | ||
| General Malgrove | Whilst leading a faction of the Gorlan Empire. | The Two Masters | The Gorlan word for master | |
| Van Houten | In the 1890s | Maurice | Named after chocolates common in the time period. | |
| Mr. Dominus | When visiting the Red Tavern in the 1890s | Masterpiece | Dominus from the Latin for lord or master of the house | |
| Mwalimu | while hiding beneath Colonel Spindleton's manor house in 1979 | Trail of the White Worm | Swahili for master in the sense of teacher | |
| Interplanetary Police Inspector Efendi | while on Secus | The Evil One | Turkish for "Master" | |
| Tremas | to deceive Nyssa on Logopolis after taking over her father's body | Logopolis | A coincidental anagram of "Master" | |
| The Portreeve | to trap the Fifth Doctor in Castrovalva | Castrovalva | ||
| Kalid | used to take control of the Xeraphin gestalt | Time-Flight | As Kalid, he affected the identity of a vaguely Arabian sorcerer. Kalid derives from the Indian Kalidasa meaning servant of Kali, an Indian goddess of time and change and usually depicted as being dark and violent. | |
| Sir Gilles Estram | to avert the signing of the Magna Carta in 1215. | The King's Demons | Estram is a simple anagram. | |
| The Sheriff | to gain access to the regenerative fountain near Eternity, California. | A Town Called Eternity | ||
| Gospodar | to access the TITAN Array in order to destroy the Chronovores | The Quantum Archangel | Serbo-Croatian and Slovenian for master | |
| Keith Potter | The End of the Line | |||
| Dr Howard Chithros | Stop the Pigeon | |||
| Major Kreer | used when allied with the Tzun in 1950s America. | First Frontier | ||
| Template:Frontier | Housewarming | |||
| Mr Seta | Used aboard the starship Gallery | Dust Breeding | Anagram of master | |
| Dr John Smith | Used while amnesiac on an unnamed colony world | Master | ||
| Bruce | occasionally reverted to impersonation of a San Franciscan paramedic named Bruce after he had taken over Bruce's body | Doctor Who | ||
| Don Maestro | Whilst trapped on Earth in the 20th century. | Mastermind | Italian for master in the sense of teacher | |
| Dook Domini | In 1931 | Mastermind | Named after The Duke of Dominoes, a trump card in an old Wallarian game of chance which beat all other suits. | |
| Alien Artefact Alpha 1 | While being kept in the Vault. | Mastermind | ||
| Dr Harcourt De'ath | to practice eye surgery on many patients, in order to literally "have eyes everywhere" | Time's Horizon, Eyes of the Master | Bar the apostrophe, De'ath is spelt the same way as "Death". | |
| Kappa Chi | Designation as CIA agent. | The Death of Hope | ||
| Master-Builder | When creating the Dalek Time Controller's new empire. | The Monster of Montmartre | ||
| The Doctor | Whilst masquerading as a future incarnation of the Doctor. | Dominion | ||
| Michael Masterson | While living in Hexford | And You Will Obey Me | ||
| Professor Yana | chameleon arch identity | Utopia | Had no known meaning of its own, but the Face of Boe made up an acronym, "You Are Not Alone" | |
| Harold Saxon | used to win Prime Ministership of the United Kingdom | Love & Monsters - Last of the Time Lords | Mister Saxon was a coincidental anagram of Master No Six; Harold is a derivative of Old English Hereweald meaning Master of the Armies. The Anglo-Saxons were invading England during the reign of King Arthur | |
| Razor | used to hide his previous identity as Prime Minister of the United Kingdom while on board a Mondasian colony ship | World Enough and Time | The Old English word for knife is seax, which is what the name Saxon originated from | |
| Missy | New name adopted after regenerating into female form | Deep Breath - present | Short for "Mistress", feminine form of "Master". | |
| Mobile Intelligence Systems Interface | Ruse allowing close contact with and delaying recognition by the Doctor | Dark Water | Backcronym from the above | |
| Miss Magister | When posing as a teacher | Yes, Missy | Latin for master | |
| Doctor Who | When practicing being good aboard a Mondasian colony ship | World Enough and Time |
Behind the scenes
- During Anthony Ainley's tenure as the Master, pseudonyms made from anagrams of "Tony Ainley" were often used in the credits — both on-screen and in Radio Times — for the Master's disguises, such as Neil Toynay for the Portreeve in Castrovalva.
- Another, craftier pseudonym was used in Radio Times for The King's Demons, when Sir Gilles was listed as being played by "James Stoker" — an anagram of "Master's Joke".
- In Sympathy for the Devil, Mark Gatiss, who voiced an alternate version of the Master, is credited as "Sam Kisgart".