Second-half strikes from Luis Suarez and Neymar eventually saw off a spirited Juve team as Barca added the biggest prize in European football to their La Liga and Copa del Rey success.
Luis Enrique’s side made the perfect start to their treble bid as Ivan Rakitic rounded off a brilliant team move in the fourth minute to give the Catalan giants an early lead.
However, Juventus fought back to grab a foothold in the game and they levelled the scores after the break thanks to Alvaro Morata’s 55th-minute strike.
The goal filled Massimiliano Allegri’s side full of confidence but just as they were starting to dominate proceedings, Suarez and Neymar sealed Barcelona’s first Champions League title since 2011.
Juventus, who were chasing a treble of their own, set their stall out early, pressing Barcelona’s back four high up the field but the Turin outfit could not take advantage of Javier Mascherano’s poor pass as Carlos Tevez’s shot failed to test Marc-Andre Ter Stegen.
Minutes later, Barca’s jitters disappeared as Lionel Messi picked out to Jordi Alba with a cross-field pass. The full-back laid the ball off to Neymar, who picked out the run of man-of-the-match Andres Iniesta into the box before he squared for Rakitic to sweep beyond Gianluigi Buffon to complete a superb team goal.
The goal settled Enrique’s side and they nearly doubled their advantage but Neymar’s shot flew inches over the bar.
Juve, who had Arturo Vidal and Paul Pogba booked in the first half, were struggling to cope with the Spanish side’s free-flowing football and had Buffon to thank for not going further behind in the 13th minute as he clawed away Dani Alves’ side-footed effort.
However, the Serie A champions started to get more joy going forward towards the end of the half as Morata curled an effort past the far post and Claudio Marchisio’s rising shot failed to hit the target.
Barcelona went close through Suarez just before the break but while they had the better of the opening 45 minutes, the Italians did enough to suggest all was not lost going into the interval.
But that Catalan class was always just under the surface as Barcelona broke quickly with five red and blue shirts pouring forward and just three Juventus players. Once again, Buffon was the Juve saviour, turning aside Suarez’s fierce strike.
Messi was then involved in some mesmerising one-touch play with Suarez and Neymar before shooting a yard past the upright, yet for all of Barcelona’s dominance, a second goal proved elusive.
And in the 55th minute, Juve were back on level terms as Marchisio’s sweet back-heel found Tevez whose shot on the turn was well saved by Ter Stegen, but the ball broke to Morata to fire home.
Suddenly, it was Juve who were full of confidence and believing they could go on to win the game. Tevez was unmarked on the edge of the box but scooped over, then Pogba shot straight into the arms of Ter Stegen.
They failed to capitalise on their dominance and they were made to pay in the 68th minute as Messi drove at the heart of the Juventus defence and shot at Buffon, who could only parry the ball into the path of Suarez. The former Liverpool striker smashed the ball home before leaping the advertising hoardings to celebrate with the Barcelona fans.
Minutes later, Neymar had the ball in the net for Barca once more, but the official behind the goal ruled it out correctly for handball.
The impressive Marchisio had Barcelona hearts racing in the dying seconds as his long-range effort was turned behind by Ter Stegen.
The final word fell to Neymar, who drilled the ball past Buffon in the final action of the match to crown Barcelona champions of Europe for a fifth time. It left Xavi, who came on with 15 minutes remaining to make his final Barca appearance, to lift the trophy in his final act as a Blaugrana player.