It is a feat completed by only two European clubs before, current French champions PSG and Welsh league winners TNS.
Celtic have won six consecutive trophies domestically, every domestic trophy since manager Brendan Rodgers took over in May 2016. Since entering the dugout at Celtic Park, Rodgers has taken Celtic to unseen heights including a 69-match unbeaten run.
While Rodgers was finding his feet at Celtic, The New Saints were celebrating their second consecutive treble of the Welsh Premiership, Welsh Cup and Welsh League cup for the 2015/2016 season.
Across the English Channel PSG had matched the feat of TNS, winning the Ligue 1 by a dominant 31 points in 2016, beating Marseille in the French Cup Final and Lille in the League cup.
TNS came close to completing the feat a third time only to beaten by Bala Town in 2016/17 Welsh Cup Final. PSG also struggled to achieve the feat a third time in a row before losing out to Monaco in the Ligue 1 title race.
If Celtic continue to dominate in this way next season they will become the first European team to complete a treble, treble.