Trinny Woodall (born Sarah-Jane Woodall 8 February 1964 in Marylebone, London) is an English fashion (fashion journalism) advisor and designer (fashion designer), television presenter and author. Woodall was raised in a wealthy family, and was privately educated. After ten years battling alcoholism and working in marketing, Woodall met Susannah Constantine in 1994, with whom she joined to write a weekly fashion column for The Daily Telegraph. This led the launch of their own internet fashion-advice business and release of their first fashion-advice book, both of which ended in disaster.

They were then both commissioned to the BBC to host What Not to Wear (What Not to Wear (UK)) in 2001. The following year Woodall and Constantine released their second book, What Not to Wear, which gained them a British Book Award (British Book Awards) and sold in excess of 670,000 copies. Woodall proceeded to co-author many fashion advice books with Constantine, with several becoming bestsellers in the United Kingdom and the United States, and having now sold over 2.5 million copies worldwide.

After co-hosting What Not to Wear for five series and appearing on The Oprah Winfrey Show as style advisors and makeover experts, Woodall and Constantine moved to ITV to host Trinny & Susannah Undress... in 2006, and Undress the Nation. After becoming the faces of Littlewoods Direct (Littlewoods Shop Direct Group), they released their own Littlewoods clothing range and latest fashion advice book, The Body Shape Bible, in 2007.