Goals from Jacob Butterfield and Ricardo Vaz Te were enough to give Barnsley a second consecutive home win.
Butterfield put the home side in front from close range, tapping home Craig Davies' knock down at the back post.
Substitute Vaz Te secured the victory when he gathered former Claret Andy Gray's pass to slot home.
Burnley's Ross Wallace saw a goal-bound effort cleared off the line, before Jay Rodriguez saw a shot ricochet off the Tykes bar.
The visitors went close early on through Wallace's effort which was cleared by Stephen Foster, while Luke Steele denied Kieran Trippier, but the hosts could have gone ahead when Jimmy McNulty headed Butterfield's corner wide.
However, they did take the lead after 21 minutes when James O'Brien crossed for Davies to head into Butterfield's path and he made no mistake.
Rodriguez then came close to marking his 100th appearance for the club with a goal, but the crossbar saved Barnsley - and Charlie Austin then spurned two chances to level the clash as the Clarets pushed for a leveller.
Clarets' skipper Chris McCann and Keith Treacy had shots go wide, before Wallace had a penalty shout waved away when he was brought down by McNulty with 18 minutes remaining.
But when David Edgar failed to deal with Gray's jinking run after 81 minutes, the experienced frontman found the unmarked Vaz Te, and he fired past Lee Grant into the bottom corner of the net.
Burnley pummelled the Barnsley goal in the final nine minutes, with Austin and Rodriguez seeing long-range efforts go wide, but it was too little too late for Eddie Howe's men, who went down to their second defeat in four days.