Robbie Willmott's brace ensured Luton leapfrogged Kidderminster to move into fifth in the Blue Square Bet Premier.
Luton took the lead when Amari Morgan-Smith broke free before squaring the ball to Willmott, who side-footed past Harriers keeper Dean Lyness.
The Hatters grabbed their second after the break when Willmott headed in Morgan-Smith's cross.
Tom Sharpe fired in a late consolation for Harriers, who have dropped out of the play-off places, from close range.
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Kidderminster manager Steve Burr told BBC Hereford and Worcester:
"We just ran out of time today although it was pleasing to get a goal and give ourselves a chance to maybe get something out of the game.
"I can't fault the lads' effort in the second half - I thought they did really well.
"But I think you could see that extra bit more that it takes if you are going to be up there and getting out of this division - perhaps Luton had that today and we didn't."