The former Leeds Rhinos and Harlequins prop, 41, had told the Championship club he would not be renewing his contract at the end of the season in order to “explore other opportunities.”
It has been decided the ex-Great Britain assistant departs now so London can have time to prepare for 2022.
Having helped Broncos win promotion in 2018, winning the Million Pound Game in Toronto, Dewsbury-born Ward was nominated for Super League Coach of the Year after London produced some terrific results before finishing joint-bottom and being cruelly relegated on the highest-ever points total.
Tom Tsang will take interim charge and Ward - who also played for Castleford Tigers and Hull KR - said: “After spending 14 years in London, with the last four years coaching I have decided it is the right time to pass on the baton at this great club.
“I have some amazing memories and will never forget that special day in Toronto and also coaching the junior sides and seeing our exceptional young talent progress from scholarship to first team as a major highlight during my time at the club.”