Millwall had to settle for a point against a resolute Barnsley after dominating much of the contest.
Josh McQuoid should have put the Lions ahead after 15 minutes but put a rebound wide when only two yards out.
Barnsley improved after the break, with Daniel Drinkwater's shot from distance blocked by Tamika Mkandawire.
But Millwall created more, with James Henry's shot dipping over, Luke Steele saving after a melee and Hameur Bouazza's free-kick flashing wide.
The Lions remain with only one league victory from their opening five matches, one point ahead of Barnsley, who also have one win in five.
McQuoid's golden opportunity came after Darius Henderson fired across goal from Bouazza's knock down, but after surging into the area he was unable to find the target with the goal gaping.
Barnsley continued to frustrate the home side but Jimmy Abdou broke clear of the shackles, only for Steele to superbly parry his shot.
The Tykes goalkeeper was again alert following a Bouazza free-kick, saving from Henderson in the resulting scramble.
He was beaten with 15 minutes remaining by another inviting Bouazza set piece, but it fizzed fractionally beyond the reach of Paul Robinson when only the slightest of touches was needed.