Brendan Rodgers' men have written their names in the record books as a result, and they will be looking to successfully defend the three trophies again next season.
The Hoops remain the team to beat in Scotland, and former midfielder and assistant manager John Collins believes that the status quo will not change until teams stop showing them too much respect.
Celtic went unbeaten last campaign, but lost four games across all domestic games this term.
That did no damage to their ultimate invincibility, though, and Collins reckons other teams' failure to take the game to Celtic while at home has cost them.
“Teams have shown Celtic too much respect, especially on their home patches," the 50-year-old and former assistant to Ronny Deila told the Scottish Sun.
“You’d think when Celtic go away their back four would be put under pressure and teams would try to stretch them.
“But what’s happened a lot of the time is they’ve sat off them and been so scared of conceding that early goal that it’s just been a procession."
Rodgers will no doubt look to further bolster his squad during the summer transfer window and, with the club's eyes set on 10-in-a-row having already won the last seven Scottish Premiership titles, beating Celtic could become much harder next term.