Harlequins director of rugby John Kingston, head coach Mark Mapletoft and forwards coach Graham Rowntree have all extended their contracts with the club.
Kingston took charge of Quins in the summer of 2016 and led the south west London club to sixth place in the Premiership table last season.
“Harlequins is on an exciting journey both on and off the field,” chief executive David Ellis said.
“The trio have a huge passion and they continue to evolve our style of play.”
Rowntree spent eight years on the coaching staff with England before leaving the national setup after the 2015 World Cup, and the 46-year-old was a coach for the British & Irish Lions for their tour of New Zealand last summer.
Harlequins have not disclosed the length of their new deals at the Twickenham Stoop.