Paul Sackey scored a second-half double for Wasps
Wasps 42 (20)
Tries: Leo, Hart, Sackey 2, Bracken
Cons: Walder 3, King
Pens: Walder 3
Harlequins 23 (11)
Tries: Monye, Easter, Luscombe
Pens: Jarvis 2
Wasps ran in five tries against Harlequins to claim a bonus point and go top of the Premiership.
Tries from Daniel Leo and John Hart, to one from Ugo Monye, helped Wasps into a 20-11 lead at the break.
Dave Walder kicked 15 points for Wasps, who saw Paul Sackey grab a second-half brace of tries, while Peter Bracken also went over.
Harlequins, who had three players sin-binned, managed consolation tries from Nick Easter and Hal Luscombe.
Harlequins, who have yet to win on their return to the top flight, scored the first points of the match when Adrian Jarvis landed a fourth-minute penalty.
Wasps went ahead after 16 minutes when Samoa international Leo went over, with Walder converting.
Quins went back in front a minute later as Monye crossed for a try but that was as good as it got for the visitors.
Walder kicked two penalties and converted Hart's try to make it 20-11 at half-time and he was on target with another penalty and conversion, this time of Sackey's try, in the 10 minutes after the break.
Sackey crossed for his second try after 67 minutes, converted by Alex King, to hand Wasps a bonus point and they scored a fifth try when Bracken rumbled over.
Quins did manage two tries of their own, through Easter and a last-minute effort from Luscombe, converted by Jarvis, but they finished well beaten.
Wasps boss Ian McGeechan:
"We let a side massively off the hook and we should be relentless about the way we play and we didn't do that today.
"We scored five tries comfortably and we could have doubled that.
"The only pleasing thing is that there's probably 50% more to come out of the team."
Harlequins boss Dean Richards:
"I'm not that concerned because I still have huge faith in my side.
"There are a lot of sides who have come here (Adams Park) and been beaten, and we're another one who has come here and been beaten quite comfortably.
"The disappointing thing for me was how we were beaten - three yellow cards was not particularly good and they scored three or four tries in that period.
"It goes to show that discipline is of paramount importance."
Wasps: Voyce; Sackey, Erinle, Staunton, Hoadley; Walder, Reddan; Payne, Ibanez, Bracken; Shaw, Palmer; Leo, Worsley, Hart.
Replacements: Ward, Mackenzie, Rees, Haskell, Amor, King, Doherty.
Harlequins: Williams; Monye, Luscombe, Deane, Keogh; Jarvis, So'oialo; Jones, Hayter, Nebbitt; Evans, Spanghero; Vos, Volley, Hala'ufia.
Replacements: Richards, Ross, Kohn, Easter, Guest, Care, Duffy.
Referee: Dave Pearson (RFU)