The Reds are soundly beaten here at the Madejski Stadium despite an improved second half showing.
Two goals in 10 first half minutes put Barnsley on the back foot here in Berkshire, with the hosts wrapping a comfortable evening up late in the second half.
Dave Edwards' header on 20 minutes and Joey Van Den Berg's 30-yard screamer gave the Royals a 2-0 lead at the break, with Jon-Dadi Bodvarsson adding a third to seal a home win and a third straight defeat without scoring for the Reds.
Paul Heckingbottom made two changes to the side who'd lost badly in the Yorkshire Derby with Leeds Utd on Saturday.
In came Ike Ugbo and Gary Gardner, with Tom Bradshaw dropped and Adam Hammill suspended.
It was a very leisurely and relaxed start to the match, neither side looking threatening and the most notable incidents being head injuries to players from either side that added a minute or two onto referee Darren Bond's watch.
On 14 minutes the game sprung into life with Brad Potts doing ever so well to block a Liam Kelly goal-bound strike.
And just five minutes later, Kelly's side were ahead from nothing.
A good defensive header from Reds skipper Angus MacDonald saw the Royals gain a corner and Kelly's whipped in cross to the front post saw Dave Edwards rise unchallenged to power a header at Adam Davies, whose attempts at stopping the shot saw him unfortunately parry the ball over the line for 1-0.
The Reds responded well with Potts feeding Harvey Barnes out wide, his cross went all the way across the box with Ugbo unable to get a toe to it.
Just on the half hour mark, Reading doubled their lead.
Van Den Berg was allowed to waltz into midfield and onwards, unchallenged and took aim from all of 30 yards, his shot was a good one and beat Davies easily to give the hosts a 2-0 lead in what had been a game of no real chances.
It was a rather uneventful and disjointed display from both sides, but at the break the home side led.
HALF TIME: Reading 2-0 Barnsley
Hecky made a triple change at the break, with MacDonald, Gardner and Ugbo replaced by Mamadou Thiam, Matty Pearson and Tom Bradshaw.
It was much better, admittedly, that wasn't difficult after the break.
Zeki Fryers saw an early free-kick power against a defender and out.
Andy Yiadom saw a speculative volley go wide.
Thiam spun his man in the box on 56 minutes before seeing his driven shot whistle just past the post.
Reading were penned in now and on 69 minutes Barnes jinked his way into a good position 25-yards out only to curl his shot just wide of the post.
Potts was next to chance his arm. He powered in an effort from 30-yards out that former Reds 'keeper Vito Mannone saved well low down.
On 77 minutes the hosts should have put the game to bed but Liam Moore saw his shot hit the inside of Davies' post and out.
10 minutes later and after great work by the impressive Thiam, Barnes found space inside the box but saw his shot hit the inside of Reading's post and it looked like the Reds' chance to fight back was over.
It was over on 88 minutes when Bodvarsson was free in space to nod home the third goal following a great save onto the bar by Davies initially.
It's three straight defeats then without a goal scored for the Reds, with Bolton Wanderers next up on Saturday.
FULL TIME: Reading 3-0 Barnsley
Reds: Davies, Yiadom, MacDonald (Pearson 45), Lindsay, Fryers, Williams, Gardner (Thiam 45), Potts, Moncur, Ugbo (Bradshaw 45).
Unused Subs: Townsend, McCarthy, Hedges, McGeehan.