England Flanker Joe Worsley, prop Will Green and wing Tom Voyce scored tries for Wasps, with fullback Mark van Gisbergen contributing the rest of the home side's points through his boot.
By restricting the Saints to a solitary try – scored by Bruce Reihana – the Londoners maintain their hot pursuit of league leaders Bath, and are now just one win away from securing a play-off berth.
Wasps – under the stewardship of England captain Lawrence Dallaglio once again – started Sunday game as they meant to go on, with Van Gisbergen notching up a penalty in the opening exchanges.
The fullback then converted after Worsley had crossed for the hosts' first try.
Two more Van Gisbergen penalties made it 16-0 at the break, and when Green scored their second try within five minutes of the second period the match was over as a contest.
Northampton finally got on the board through Reihana's try, but Wasps finished things off with a further Van Gisbergen penalty and a third try through Voyce.
Whilst Wasps clearly benefited from the return of their Test stars, Northampton coach Wayne Smith might rue his decision to leave his England aces – Matt Dawson and Steve Thompson – on the bench.
For London Wasps:Tries: Worsley, Green, VoyceCons: Van Gisbergen 2Pens: Van Gisbergen 4
For Northampton Saints:Try: Reihana