The win constitutes Wasps' ninth consecutive Premiership win – and the Titans' 18th straight defeat in the competition.
The Titans sniffed a chance when Wasps fly-half Alex King hit the post with a penalty early in the game, but evergreen scrum-half Rob Howley made immediate amends with a 60-yard sprint down the left to score.
King was on target with the conversion in the eighth minute, before Rotherham fly-half Phil Jones pulled back six points with two fine penalty kicks.
King hit back with a place-kick of his own, before former All Black prop Craig Dowd was bundled across the line on the stroke of half-time for a converted try.
A determined Rotherham tried to take control in the opening minutes of the second half, but former Scotland wing Kenny Logan managed to get to grips with a loose ball to scamper across the line for the home side.
Rotherham pressed on and were rewarded for their efforts when centre Jon Pritchard crossed for a try, but Wasps extinguished any hopes of a Titans revival by hitting back with two quick-fire tries from Tom Voyce and Mark Denney.
For London Wasps:Tries: Howley, Dowd, Logan, Voyce, Denney Cons: King 4Pens: King 2
For Rotherham Titans:Try: PritchardPens: Jones 2