Burns, Penalty Try, Sloan, Lindsay-Hague
Botica (3), Clegg
Evans, Monahan, d'Apice
Ollie Lindsay-Hague; Seb Stegmann, Harry Sloan, Ben Botica, Charlie Walker; Rory Clegg, Jordan Burns; Darryl Marfo, Rob Buchanan, Kyle Sinckler; Sam Twomey, Charlie Matthews; Joe Trayfoot, Dave Ward (capt), Jack Clifford
Harry Allen, Nick Mayhew, Will Collier, Frankie Taggart, James Chisholm, Henry Taylor, Louis Grimoldby, Miles Mantella
Steph Reynolds; Ian Clark, Drew Locke, George Boulton, Shane Monahan; Tim Taylor, Dave Lewis; Yann Thomas, Koree Britton, Dario Chistolini; Peter Buxton (capt), Dale Critchley; Matt Cox, Rob Langley, Gareth Evans
Tommaso d'Apice, James Gibbons, Tom Heard, Tom Ailes, Alex Woodburn, Brad Field, Kai Done, Graham Spiers
Gloucester were also badly hurt by losing two men to the sin bin in a first half during which Quins effectively sealed the game.
It was a typical Quins performance, featuring plenty of pace and offloading with Dave Ward, freed from the usual confines of the front row, enjoying himself hugely at openside.
Gloucester refused to throw in the towel, even when staring down the barrel of a heavy defeat, and finally gained some reward for their efforts with three second half tries.
But, it was all too little, too late and Harlequins deservedly advance to the final.
The home team were quickly out of the blocks. The pack laid the foundations, and a smart offload gave scrum half Jordan Burns to the chance to dart over from close range, the conversion making it 7-0.
Referee David Rose was coming down hard on clearing the tackle area in the opening stages. He was consistent to be fair, penalising both sides, but Ben Botica was able to make it 10-0 after one such decision.
Botica was short and wide with another attempt on 17 minutes, but Gloucester were walking a disciplinary tightrope and lock Dale Critchley was sinbinned shortly afterwards. Botica duly made it 13-0.
A man light, Gloucester were starting to struggle in the scrum and, after a couple of resets, David Rose awarded a penalty try.
Peter Buxton was sent to the sinbin as Botica converted, and the centre then tore apart the midfield defence, as his jinking run put midfield partner Harry Sloan in for another try. Rory Clegg converted for 27-0.
Gloucester dug deep and finished the half strongly as the sinbinned players returned. However, they were denied a morale boosting try on the stroke of half time as referee Rose spotted a knock on near the Quins line.
Gloucester competed gamely in the opening exchanges of the second half, but went further behind as Botica slotted a 51st minute penalty.
However, the Cherry and Whites finally started to makes some gains in attack, and home number eight Jack Clifford was yellow carded for interfering with the ball at a ruck.
And the reward finally came for Gloucester as they disrupted a Quins scrum near the home line. The ball squirted loose and Gareth Evans pounced to score.
Botica added another penalty on 61 minutes to extend the lead to 33-5, before Gloucester's sense of injustice grew as Rob Langley was denied a try for blocking.
To rub salt into the wound, Seb Stegmann's break put Dave Ward clear into the Gloucester 22. The hooker cum flanker was felled by Shane Monahan, but offloaded to Ollie Lindsay-Hague to score. The conversion made it 40-5.
To their credit, Gloucester kept going right until the very end and tries from Shane Monahan and Tommaso d'Apice gave the scoreline a more flattering appearance.
However, the win was a deserved one for the home side and Gloucester can have no qualms with the outcome.