Martin Cranie’s cruel own-goal earned Yeovil a point at Huish Park.
Cranie, a Yeovil lad, diverted home A-Jay Leitch-Smith’s shot with 14 minutes to go after the hosts had dominated the closing stages.
The battling Reds are now unbeaten in four League One games, however, and can continue to look forward with confidence.
Conor Hourihane gave the visitors the lead in the 27th minute when he cracked home a shot from 25 yards.
The superbly-struck effort flew past ‘keeper Chris Weale via the slightest of deflections off Glovers’ midfielder Joe Edwards.
After the break the hosts rallied with an improved effort in the third quarter of the match.
Substitute Kieffer Moore forced Adam Davies into a smart stop at his near post, while Edwards also went close.
A-Jay Leitch-Smith also saw a crashing drive flick off Luke Berry and drift narrowly wide.
At the other end, Reds youngster Brad Abbott drilled a shot straight at Weale.
However, it was the Glovers who eventually grabbed the goal their second-half performance probably deserved.
Leitch-Smith lashed in a snapshot and Reds’ skipper Martin Cranie - playing against his home-town club - could only divert an attempted clearance past a stunned Davies.
Hourihane was forced to clear a Moore header off the line as the Glovers almost snatched a late victory.
Yeovil (4-4-2): Weale; Sokolik, Martin, Nugent, Smith; Dawson, Edwards, Gillett, Foley; Leitch-Smith, Hayter. Subs: Krysiak, Maloney, Moore, Hoskins, Twumasi, Ralph, Brooks.
Barnsley (4-4-2): Davies; Brown, Cranie, Nyatanga, Dudgeon; Berry, Abbott, Hourihane, Treacy; Winnall, Lita. Subs: Turnbull, Jennings, Hemmings, Digby, M’voto, Cole, Bree.
Referee: Gavin Ward (Surrey).