Steven Gerrard's Rangers side became only the second team to win the Scottish Premiership and go a full season without losing a game after the champions beat Aberdeen 4-0 at home on the final day on Saturday.
Rangers won all 19 of their home games at Ibrox and equalled the league record of 26 clean sheets in the campaign. They also set a record by conceding only 13 goals in their 32 wins and six draws.
Celtic, the first side to go unbeaten in the 2016-17 season, finished 25 points behind Rangers, who sealed the title in March to deny their archrivals a 10th straight title.
"It feels good, it's been a while since I've had the smell of champagne ... I'm actually enjoying it," Gerrard told Sky Sports after he was soaked in champagne by Rangers striker Alfredo Morelos.
"I was asked to come here at a really difficult time ... It was about having a vision, having the right people in the right places, the right support from the board. We fought every day for three years to get to this point."
Although fans are not allowed inside the stadium due to COVID-19 restrictions, many gathered outside with banners and blue flares to celebrate their "Invincibles" campaign.