Around 35 marching bands are due to take part in the event, with the parades returning to Edinburgh for the first time in three years this summer.
The march will start at The Meadows at noon before heading down Middle Meadow Walk onto Forrest Road, George IV Bridge, Lawnmarket, High Street, Abbey Road and Regent Road.
The application by The Loyal Orange Institution of Scotland to hold the three summer parades was approved by the City of Edinburgh Council’s licensing committee in March.
The event today is being staged to mark the Queen’s Platinum Jubilee, the committee was told.
Those taking part include the Grand Orange Lodge of Scotland, County Grand Lodge of Glasgow and the Associated Clubs of the Apprentice Boys of Derry.