It's the second time Wheeler, pictured, has been relieved of his duties at the Essex-based club in little over a year.
In August last season, Wheeler and Billericay parted ways after their first defeat of the season, only to make a sensational return after just 147 days.
The ex-Maidstone boss leaves Ricay currently sitting seventh in the National League South with 19 points from their opening 11 games.
“We can now confirm that Harry Wheeler has been relieved of his duties and has left the club after a recent meeting with the owner,” read a statement on the club’s website.
“Differences of opinion have led to the decision and the owner feels changes needed to be made.
“Jamie O’Hara will take control of first team duties and will look to immediately make his mark by looking at bringing in some young talented academy players to add to the good experience we have.
“From all at the club we wish Harry all the best for the future and we thank him for all his efforts and successes in his time here.”