The free event, which is the biggest festival of its kind ever held in the capital, runs from 18:30 GMT to 22:30 GMT until 17 January.
Thirty locations will be illuminated around Piccadilly, Mayfair, King's Cross, Trafalgar Square and Westminster.
On Regent Street, a life-size animated elephant will appear from a dust cloud.
Visitors to Oxford Circus will see the multicoloured cloud of artist Janet Echelman's 1.8 London floating above them.
Patrice Warrener's The Light of the Spirit projects coloured light onto statues at Westminster Abbey.
And ethereal figures seem to fall through the air in St James's Square, where Cedric Le Borgne is showing Les Voyageurs (The Travellers).
Transport for London (TfL) have warned that roads will be closed and Tube stations will be busier than usual in the areas where the festival is being held.
A number of buses will be diverted or terminate early.
It has been created by producers Artichoke, who held a similar event in Durham.
As well as a "huge" production crew, the company has recruited volunteers from Team London, which supported the London Olympics, to help guide people around the installations.
"The arts should be free and available to everyone," Artichoke's director Helen Marriage told BBC London.
Some of London's most famous locations will be transformed by light installations for the Lumiere festival.