The hosts looked set to make significant ground on the top six when Chris Killen opened the scoring two minutes into the second half.
But David Wheater's own goal ensured Reading claimed a deserved share of the spoils to extend their unbeaten run to five league games.
The Royals had won eight of their last nine Championship outings prior to today's game and enjoyed the better of the first half, with Shane Long seeing a header superbly saved by Brad Jones.
And although Killen headed Boro into the lead after the interval, Reading responded well and got back on level terms when Wheater turned Jimmy Kebe's cross into his own net.
Jones replaced Danny Coyne in goal for Middlesbrough as one of five changes from the midweek draw at Derby.
There were also recalls for Justin Hoyte, Jonathan Grounds, Emanuel Pogatetz and Jonathan Franks.
Reading boss Brian McDermott named an unchanged starting XI as his side looked to continue their outstanding recent form.
Boro were the first to threaten in a relatively quiet opening to the game, Killen warming the palms of Adam Federici with a hopeful effort from 25 yards.
Reading responded with centre-half Matt Mills heading narrowly wide from Andy Griffin's cross and Kebe's dangerous cross forcing Hoyte into a hurried clearance.
Killen went close again for Boro in the 19th minute with a header that bounced just past Federici's right-hand post.
But the visitors enjoyed the majority of possession for the remainder of the half and almost took the lead on the half hour.
Long met Jobi McAnuff's cross with a powerful header, but Jones pulled off a wonderful one-handed save to keep the scores level.
Reading continued to look the most likely to open the scoring as the interval approached, although Federici had to be alert to keep out a low strike from Barry Robson following a Boro breakaway.
Although they had been second best in the opening 45 minutes, it was the hosts who went in front early in the second half as Killen met Hoyte's cross with a looping header that sailed over Federici and into the top-left corner.
The goal lifted Boro and Gary O'Neil almost doubled their advantage in fortuitous fashion when his attempted cross forced Federici to tip over the bar.
Scott McDonald also tested the Royals keeper with a shot from 20 yards before Reading stirred back into life, with Kebe testing Jones at his near post.
And it was Kebe who helped the visitors draw level in the 63rd minute as he skipped past two men before firing in a low cross which deflected into the net off the unfortunate Wheater.
Both sides pushed for a winner, with Killen seeing another header saved by Federici and Brian Howard volleying wide for Reading.
There was further drama in the closing stages as Federici denied Killen yet again.
Royals top-scorer Gylfi Sigurdsson then fired in a low free-kick which almost caught out Jones, but the scores remained level.