Trousers

Trousers were an item of clothing typically worn to cover the legs. A suit which included trousers was known as a trouser suit.

Worn by the Doctor
The First Doctor wore grey tartan trousers. (TV: An Unearthly Child-The Tenth Planet, The Three Doctors, The Five Doctors, Twice Upon A Time)

The Second Doctor wore tartan trousers done in grey, (TV: The Power of the Daleks-The War Games, The Three Doctors, The Five Doctors, The Two Doctors) or yellow with green stripes. (COMIC: Comic Relief Comic)

The Third Doctor wore black trousers. (TV: Spearhead from Space-Planet of the Spiders, The Three Doctors, The Five Doctors)

The Sixth Doctor typically wore royal yellow trousers with black stripes. (TV: The Twin Dilemma-Time and the Rani) While acting as his successor, Jack Harkness wore the Sixth Doctor's coat along with his seventh favourite waistcoat and yellow-stripped trousers. (AUDIO: Piece of Mind)

The Seventh Doctor wore plaid trousers done in grey brown, (TV: Time and the Rani-Survival) or green. (TV: Doctor Who)

The Eighth Doctor wore trousers done in loden green, (TV: Doctor Who) mauve, (COMIC: Dreadnought) sapphire blue, (AUDIO: Time Works) fern green, (AUDIO: Absolution) scarlet, (PROSE: The Eye of the Tyger) or tan brown. (COMIC: The Pictures of Josephine Day, A Matter of Life and Death, The Lost Dimension, Empire of the Wolf, TV: The Night of the Doctor)

Throughout his life, the War Doctor wore tan trousers (COMIC: The Clockwise War, The Lost Dimension, The Whole Thing's Bananas, WC: Doctors Assemble) right up to his death after the Fall of Gallifrey. (TV: The Day of the Doctor)

The Tenth Doctor wore trouser suits of pinstripe done on dark brown and light blue, (TV: The Christmas Invasion-The End of Time, The Day of the Doctor) or navy and crimson. (TV: Smith and Jones-Dreamland) He also wore black trousers as part of his tuxedos. (TV: Rise of the Cybermen|The Age of Steel, The Lazarus Experiment, Voyage of the Damned)

The Eleventh Doctor initially wore midnight blue trousers. (TV: The Eleventh Hour)

The Twelfth Doctor wore plain trousers done in indigo, (TV: Deep Breath) or black. (TV: Under the Lake) He also wore baggy plaid trousers in gunmetal grey, (TV: The Doctor's Meditation), Prussian blue and alabaster, (TV: The Girl Who Died), navy and crimson, (TV: The Woman Who Lived) or bottle green. (COMIC: The Ministry of Time)

The Thirteenth Doctor wore teal capri trousers. (TV: The Woman Who Fell to Earth-The Power of the Doctor) She also wore black trousers as part of her tuxedo. (TV: Spyfall)

The Fourteenth Doctor wore trousers of black and turquoise tartan. (TV: The Power of the Doctor)

The Curator, a future version of the Doctor, wore mahogany trousers when he looked similar to the Fourth Doctor. (TV: The Day of the Doctor)

Worn by the Master
The Master wore trousers on many colours.

The UNIT Master wore black trousers. (TV: Terror of the Autons-Frontier in Space)

The Master who stole Tremas's body wore black trousers. (TV: Logopolis-Survival)

When posing as Professor Yana, the War Master wore black trousers up to his death. (TV: Utopia)

When posing as Harold Saxon, the Saxon Master wore a black trouser suit. (TV: The Sound of Drums|Last of the Time Lords) He also wore gunmetal cargo trousers when in hiding, (TV: The End of Time) then wore dark trousers up to his death. (TV: The Doctor Falls)

The Spy Master wore black tuxedo trousers when posing as O. He briefly wore black trousers when he met the Thirteenth Doctor on London during 1834, then wore khaki green trousers when posing as a Nazi on Paris during 1941. (TV: Spyfall) Mainly, he wore navy trousers with orange plaid symbols. (TV: Spyfall-The Timeless Children) He also wore trousers done in charcoal tweed or black cotton as well as the Thirteenth Doctor's capris when possessing her body. (TV: The Power of the Doctor)

Worn by Companions
Barbara Wright wore black trousers with her jumpers. (TV: The Keys of Marinus, The Web Planet, The Space Museum, The Chase, etc.)

Polly Wright wore black trousers when she helped to fight Telosian Cybermen on the Moonbase during 2070. (TV: The Moonbase)

Victoria Waterfield wore chestnut brown trousers when she first met the Great Intelligence and some Robot Yeti on Tibet during 1935, (TV: The Abominable Snowmen) and when she met Ice Warriors on Brittanicus Base. (TV: The Ice Warriors)

Sarah Jane Smith gained camouflaged trousers from Skaro during the Dalek's origins, (TV: Genesis of the Daleks) and also wore it during her encounter with Nomad Cybermen. (TV: Revenge of the Cybermen) She also wore mauve trousers met Morbius, Solon, Condo, and the Sisterhood of Karn. (TV: The Brain of Morbius)

Nyssa wore a trouser suit of plum purple velvet. (PROSE: Four to Doomsday, Earthshock, Time Flight, Arc of Infinity)

Tegan Jovanka wore Prussian blue trousers during the Master's Dalek Plan. (TV: The Power of the Doctor)

Ace wore black trousers during her travels. (TV: Battlefield-Survival) She wore black trousers as part of her tuxedo when she went to Gabriel Chase on 1883. (TV: Ghost Light) During her time as CEO of A Charitable Earth, she wore a black and white pinstripe trouser suit. (AUDIO: Quantum of Axos; TV: The Power of the Doctor)

Cinder wore camouflaged trousers. (COMIC: The Bidding War, Relative Dimensions)

Rose Tyler's personal growth during her travels with the Doctor began to reflect itself in her clothing choices as she became more confident and assertive, swapping her jeans for slim black trousers. (TV: The Long Game, Bad Wolf/The Parting of the Ways, New Earth, Fear Her, Army of Ghosts/Doomsday, The Stolent Earth/Journey's End)

While investigating Adipose Industries in 2009, Donna Noble wore a black trouser suit on Wednesday. (TV: Partners in Crime)

Tegan Jovanka wore Prussian blue trousers during the Master's Dalek Plan. (TV: The Power of the Doctor)

Others
At Coal Hill School in the 1960s, girls were not permitted to wear trousers. Basil James Carker, the headmaster, had turned down dozens of petitions that girls be allowed to wear trousers to school. They instead had to wear skirts or tunics. Susan Foreman commented in her diary that "[she thought] he'd be happiest if we had to wear Mohammedan veils and Idaho potato-sacks". (PROSE: Time and Relative)

Ianto Jones used a trouser press. (AUDIO: Believe)

Cathy Salt wore a brown trouser suit. (TV: Boom Town)

Penny Carter wore a grey trouser suit. (TV: Partners in Crime)

Allison Williams wore tan trousers when she helped the Seventh Doctor during the Hand of Omega Incident. (TV: Remembrance of the Daleks)

Jenny Flint wore olive green trousers with her waistcoats, shirts and cravats. (TV: A Good Man Goes to War)

Henry Van Statten wore a black and white pinstripe trouser suit. (TV: Dalek)

Kyle wore bottle green trousers, up to when she was killed by a Neomorph Cyberman. (TV: Earthshock)

Diane Holmes wore olive trousers while adapting to the 21st century. (TV: Out of Time)

Diagoras wore a black pinstripe trouser suit as did Dalek Sec when he fused with him to become a Human Dalek. (TV: Daleks in Manhattan|Evolution of the Daleks)

The Ringmaster of the Psychic Circus wore maroon gingham trousers. (TV: The Greatest Show in the Galaxy)

Mr Copper wore olive tweed trousers. Bannakaffalatta and Rickston Slade wore black trousers as part of their tuxedos. (TV: Voyage of the Damned)

Jackson Lake wore black trousers when he and Rosita helped the Tenth Doctor foil some Cybus Cybermen on London during the year 1851. (TV: The Next Doctor)

Vienna Salvatori wore charcoal trousers. (AUDIO: The Shadow Heart-Vengeance)

Having sustained a severe leg wound, blood was spread across Stella's trousers. (PROSE: Prisoner of the Daleks)

When working with the thermocoupling]s in the Doctor's TARDIS, Rory Williams became distracted by Amy Pond's skirt, visible through the glass floor, and dropped the coupling, causing the TARDIS to materialise inside itself. (TV: Space) After the mess had been sorted, the Eleventh Doctor told Amy to put some trousers on. (TV: Time)

Information from invalid sources
Deborah (as played by Minnie Driver in the Doctor Who serial Father Time) had a "dowdy" appearance, as described by a costume designer, executed using unflattering jumpers and corduroy trousers. (NOTVALID: Father Time: "Set Visit")