The competition will launch in the April issue and run simultaneously on Glamour.com.
Couples are invited to submit three recent photographs of themselves by email or by uploading them to Glamour's Facebook page.
Glamour style scouts will also scour the streets of London, Manchester, Birmingham, Cardiff, Edinburgh and Belfast from 12th to 16th March to flush out the sharpest dressed couples nationwide.
The closing date for entries is 23 March and readers can vote for their favourites to join the shortlist on Glamour.com.
Jo Elvin, editor of Glamour said: "We know that Glamour readers are an army of chic, style-obsessed women.
"Now's their chance to show the influence they've had on their other halves. And with our fabulous partner my-wardrobe.com, the winners could not ask for a more amazingly fashionable prize."
The finalists will be announced in the June issue of Glamour before the grand finalists are brought to London to meet a judging panel consisting of Dannii Minogue, Dannii's project D designer Tabitha Somerset Webb, TV presenter Dermot O'Leary, my-wardrobe.com founder Sarah Curran, and Glamour editor Jo Elvin.
O'Leary said the UK has great fashion credentials but advised couples to "raise your game".
The winning couple will be revealed in a photo shoot for the September issue of the magazine, which goes on sale on 9 August, when they will receive their prize of £20,000 to spend together at my-wardrobe.com.