Knocked off the top of the table by a home defeat to Barnsley on Good Friday, the Hatters found themselves a goal down as struggling Torquay tore into them from the first whistle.
Bayo Akinfenwa side-footed home his 13th goal of the season after only six minutes, after Luton keeper Marlon Beresford had done well to block Jo Kuffour's first shot.
Kuffour and winger Aaron Brown also went close as Torquay threatened to cause a real upset.
But skipper Kevin Nicholls' 22nd minute equaliser seemed to knock the Gulls out of their stride.
Nicholls stabbed the ball into the roof of the net after Steve Howard's first header from Paul Underwood's corner had been parried by Andy Marriott.
Ten minutes later Peter Holmes beat Marriott with a thumping header from Kevin Foley's pinpoint right-wing cross.
Torquay were lucky to be only 2-1 down at half-time – Marriott scooped one Howard effort onto his bar and over – but centre-forward Howard did not have long to wait for his 20th goal of the season.
Marriott could only parry Underwood's cross-shot and Howard nodded the ball over the line, taking the net off the woodwork in the process.
Torquay had a chance to grab a lifeline on the hour when Underwood handled.
But Beresford dived to his right to push Akinfenwa's penalty onto the post and away.
It was plain-sailing for Luton after that, especially with the news that automatic promotion rivals Hull were losing at Oldham.
Rowan Vine wrapped it up in the 71st minute with a sweet left-foot half-volley from Ahmet Brkovic's throughball.
Nearly all the other results went against Torquay, who are now six points adrift of safety with only six games to go.