Scrum-half Eoin Reddin and Rob Hoadley crossed the whitewash for the visitors while Alex King added one conversion to his three penalties.
Despite creating plenty of scoring opportunities, Northampton could only score three minutes from time through replacement wing Rhodri Davies with Bruce Reihana adding the conversion and a penalty, while Carlos Spencer landed a drop-goal.
Tom Voyce, making a record 57th consecutive league appearance, was full of running for Wasps in a frenetic opening salvo. King gave Wasps the lead after ten minutes with a penalty, but Saints began to throw the ball around and should have made more of their chances.
John Rudd and Mark Robinson both made solid breaks for Saints but could not link up with their support runners.
Wasps were down to 14 men when Hoadley was sin-binned for a late tackle on Rudd, but Northampton could not make the extra man count.
Spencer finally got Saints on the board with a drop-goal and Reihana opened his account with a 40-metre penalty.
Immediately after the break, Wasps sent in Simon Shaw and Lawrence Dallaglio into the fray, with Dallaglio making an immediate impact.
The former England skipper powered his way off the back of a midfield scrum, before finding John Hart. Hart then linked with Voyce to send scrum-half Reddin on a 30metre sprint to the corner.
King could not convert but made amends with a penalty 10 minutes later to give Wasps an eight point lead.
Northampton were denied a try when referee Rob Debney judged that prop Chris Budgen had not grounded the ball.
Three minutes from time Davies went on a superb solo run, chipped ahead and then beat Voyce for Saints first try.
Reihana converted but Wasps hit back from the restart as Hoadley intercepted Spencer’s pass and ran in 25 metres to score which King converted.