Pant reached the landmark during the second session on Day 4 of the first Test against Sri Lanka in Galle, hitting a six off pacer Lahiru Kumara.
Fourth cricketer to reach milestone
With the feat, Pant became only the fourth cricketer in the world to hit 100 sixes in Test cricket.
He joined an elite list featuring England's Ben Stokes, former New Zealand captain Brendon McCullum and Australian wicketkeeper-batter Adam Gilchrist.
Fastest to 100 Test sixes
Pant also achieved the milestone in fewer than 80 Test matches, making him the fastest cricketer to reach 100 sixes in the longest format, according to media reports.
The achievement further underlines Pant's reputation as one of the most aggressive and impactful wicketkeeper-batters in modern Test cricket.
Another milestone for Pant
The landmark adds another record to Pant's Test career, with his attacking approach and ability to change the momentum of a match making him a key part of India's red-ball setup.
His latest achievement also puts him alongside some of the most destructive Test batters in cricket history.