Wednesday went ahead early on when new permanent signing Gary Hooper was left free in the home area to score easily for a third successive match.
Reading squandered a first-half penalty when Matej Vydra struck a post from the spot, but they levelled 16 minutes from the end as defender Jake Cooper nodded home.
Wednesday arrived in Berkshire in good form after winning four successive matches in all competitions, while the Royals had only won three of eight games since manager Brian McDermott returned to the club.
Wednesday started the better and, following a clever pre-planned move from a Ross Wallace corner, Barry Bannan’s low drive struck a post.
The Wednesday pressure swiftly gathered momentum and they went ahead in the 10th minute.
Good build-up play on the right by Fernando Forestieri gave Hooper the time and space to fire past home goalkeeper Ali Al Habsi.
It was Hooper’s fifth goal in three matches and seventh in 13 league games. He joined Wednesday permanently this week after playing on loan from Norwich City since October.
Reading gradually worked their way back into the game and were rewarded when Vydra was brought down in the area by Wednesday captain Glenn Loovens.
Vydra, who scored a second-half hat trick in Reading’s midweek 5-2 win over Huddersfield in their FA Cup third-round replay, struck the penalty well but it crashed against keeper Keiren Westwood’s left-hand post and away to safety.
Reading still persisted in search of the equaliser but were mainly restricted to long-range efforts that barely troubled Westwood.
Anton Ferdinand, debutant George Evans - a free transfer signing from Manchester City - Oliver Norwood and Jordan Obita all wasted decent openings.
The pattern continued after the interval, with Westwood having to save a 20-yard attempt by Danny Williams.
Wednesday appeared content to hold what they had but, on a rare break forward, Bannan flashed an effort across the face of the home goal.
Yann Kermorgant, a £500,000 signing from AFC Bournemouth, was brought on by McDermott at half time to make his debut.
But the Frenchman tried to be too ambitious from a 25-yard free kick and blazed it well over Westwood’s crossbar.
Wednesday stood strong at the back and, when they briefly emerged from their defensive shell, Kieran Lee crossed from the right and Forestieri saw his close-range shot blocked.
But Reading were back on level terms in the 74th minute, when centre back Cooper rose to meet Norwood’s corner and headed powerfully home for his first goal of the season.
Wednesday almost conceded a second in the last minute, when Kermorgant narrowly failed to connect with Norwood’s cross, but they held on for a draw.
“I reckon that we can be more strong in the second half of the season,” Owls boss Carlos Carvalhal said. “We are in a much better position than at the start of the season and we are winning a lot of points. So let’s see what we can do.
“We started the game very well with very high quality. But we lost some energy and the capacity to keep the ball in attack.
“The result wasn’t what we liked or what we wanted but it’s the reality. Reading had much more of the ball but we controlled the game. We always expected to create something on the counter-attack.”