Julian Joachim rescued a point for
Coventry with a last-ditch equaliser.
Gillingham's Tommy Johnson's second-half brace looked to have secured victory at Highfield Road but they failed to hang onto their lead.
Coventry started the second half strongly with Stephen Warnock shooting just wide of the target.
And they got their reward 10 minutes after the re-start.
The ball was worked to Julian Joachim following good build-up play and the former Aston Villa striker made no mistake as he put his side ahead with a clinical finish.
Joachim had another effort on goal just four minutes later, but this time his shot was blocked by Ian Cox.
Gillingham levelled matters against the run of play after 66 minutes.
Johnson, on as a first-half replacement for the injured Rod Wallace, hammered home a superb equaliser from 25 yards.
And the visitors almost took the lead five minutes later when Mamady Sidibe's corner found Cox, whose header was tipped over by Coventry keeper Gavin Ward.
Gillingham stunned Coventry by taking the lead five minutes from time when Johnson scored from 20 yards, before Joachim staged his late show to snatch a point for the Sky Blues.
Coventry had shaded the opening 45 minutes but were frustrated by a Gillingham side who kept them at bay with some resolute defending.
Gillingham's John Hills had the first effort on goal after 10 minutes, but his
effort flew wide of the target.
Both sides struggled to carve out any clear-cut opportunities early on.
Coventry's Steve Staunton steered a header wide of the target.
Doyle then had a goalbound shot blocked as the home side worked their way back
into the game.
Gary McAllister's side looked more impressive as the half wore on and another chance went begging as Patrick Suffo sent a header past the post after 28 minutes.
It proved a brief respite, though, as Chris Hope cleared a dangerous cross from Joachim, who was to win a point with his late equaliser.
Coventry: Ward, Pead, Konjic, Davenport, Staunton, Barrett,
Safri, Warnock, Doyle, Suffo, Joachim. Subs: Shearer, Whing,
Adebola, Morrell, Jackson.
Gillingham: Brown, Nosworthy, Cox, Hope, Hills, Wallace,
Hessenthaler, Smith, Southall, Shaw, Mamady Sidibe. Subs: Bossu,
Tommy Johnson, Saunders, Spiller, Perpetuini.
Referee: S Dunn (Gloucestershire)