A jacket was an item of clothing worn on the upper body, often over a shirt, waistcoat and/or jumper.
Worn by the Doctor
The Doctor wore several different kinds of jackets throughout his life. The First Doctor wore a dark lounge jacket for much of his life, (TV: An Unearthly Child - The Tenth Planet) while the Second Doctor wore a rumpled black suit jacket for all of his. (TV: The Power of the Daleks onwards) The Third Doctor alternated between numerous velvet smoking jackets of many different colours, (TV: Spearhead from Space - Planet of the Spiders) and the Fourth Doctor briefly adopted two different corduroy jackets, a red shooting jacket immediately following his regeneration (TV: Robot - Planet of Evil) and a burgundy jacket close to the end of his life. (TV: The Leisure Hive)
The Seventh Doctor wore several jackets of varied colour, initially adopting an off-white safari-style jacket (TV: Time and the Rani onwards) which he later replaced with a chocolate brown one. (TV: Battlefield onwards) He introduced several others, including a cream one made of linen (PROSE: White Darkness onwards) and another, lighter brown one, this time made of tweed, (TV: Doctor Who) later in his life.
The Eighth, (AUDIO: The Great War) War (TV: The Day of the Doctor) and Ninth Doctors (TV: Rose) all wore jackets made of leather, while the Tenth Doctor wore two different pinstripe jackets as part of his pair of pinstripe suits. (TV: The Christmas Invasion, Smith and Jones)
The Eleventh Doctor wore several jackets made of tweed, initially adopting one made of a simple Donegal tweed, (TV: The Eleventh Hour - The Big Bang) which he briefly replaced with a Harris tweed (TV: Victory of the Daleks - Flesh and Stone) before adopting a new jacket in a Shetland tweed, which he used as part of his regular attire until the end of his search for Clara Oswald. (TV: A Christmas Carol - The Angels Take Manhattan)
Worn by companions
Ace wore a bomber jacket covered in patches, badges and pins, among them a Charlton Athletic badge, (TV: The Happiness Patrol) Flowerchild's earring, (TV: The Greatest Show in the Galaxy, Silver Nemesis) and Captain Sorin's shiny cap insignia. (TV: The Curse of Fenric, Survival)
Worn by others
The Fliis took the form of leather jackets so they could bond with humans as part of their plan to invade 20th century Earth. (COMIC: Fashion Victims)