Dan Hipkiss scored the opening try
Leicester: (16) 27
Tries: Hipkiss, Rabeni
Pens: Goode 5
Gloucester: (9) 27
Tries: Forrester, Allen
Pens: Walker 2, Davies
Drops: Walker 2
Gloucester snatched a draw with a penalty from Brad Davies five minutes from time as Leicester let victory slip from their grasp at Welford Road.
Centre Dan Hipkiss scored the only try of the first half as the Tigers, with three Andy Goode penalties, led 16-9.
But Willie Walker, who kicked 14 points including two drop-goals, kept the visitors in it and James Forrester and Anthony Allen scored second-half tries.
Tigers led 24-14 after a Seru Rabeni try, but could not close out victory.
While the hosts will be furious at letting a second home victory of the season slip, the result provided further evidence of Gloucester's re-emergence as a Premiership force.
They were the last team to win at Welford Road in the Premiership, since when Leicester have strung together an unbeaten 27-match run.
Leicester head coach Pat Howard:
"Our performance was particularly bad. We were naive, had some unlucky calls and made too many mistakes.
"They made us work hard for our tries and the tries we conceded were soft.
"As a team performance overall it was pretty poor. We know that and we will deal with it."
Gloucester head coach Dean Ryan:
"This was a heartening performance. It was an illustration of where we are because there were some good points and some not-so-good points.
"I didn't think we played very well in the first half. We lacked a bit of decisiveness and we were much better and sharper in the second half.
"We are slightly miffed because we thought we would have won. Their first try was cheap and the second try could have been stopped as well."
Leicester: Vesty; Murphy, Hipkiss, Cornwell, Rabeni; Goode, Bemand; Ayerza, Chuter, White; Cullen, Hamilton; Crane, Abraham, Corry (capt).
Replacements: Buckland, Castrogiovanni, Moody, Deacon, Murphy, Burke, Varndell.
Gloucester: Morgan; Bailey, Keil, Allen, Foster; Walker, Richards; Collazo, Azam, Califano; James, Bortolami (capt); Buxton, Hazell, Forrester.
Replacements: Davies, Forster, Wood, Eustace, Boer, Davies, Lawson.