The in-form 'Cherry and Whites' outfit, led by openside flanker and try-scorer Jake Boer, managed to secure a four-try bonus point and in the process secured a trip to HQ for the May Final.
French fly-half Ludovic Mercier scored Gloucester's fourth and final try, adding three conversions with his accurate left boot, with England Sevens star Henry Paul slotting one penalty goal to go with his try in the 20th minute. Paul took over the kicking duties when Mercier was helped from the field with a leg injury late in the match.
Paul, with some clever footwork, and Boer – after a good run from fellow South African Thinus Delport – scored first-half tries, both of which were converted by Mercier, to put the home team ahead by 14-6 at half-time, Gloucester outscoring the visitors by a similar scoreline, 15-5, in the second half.
Speedy wing James Simpson-Daniel profited from an error by his England colleague Will Greenwood eight minutes after the break, while Mercier, before hurting his leg, scored the bonus-point clinching try through a chip ahead just four minutes later.
For Gloucester:Tries: Paul, Boer, Simpson-Daniel, MercierCons: Mercier 3Pen: Paul
For NEC Harlequins:Try: FugaPens: Burke 2