"It's a testament to the love we have received from millions of Mi Fans since our inception.
"There have been brands who entered the market before us, yet are nowhere close to the astounding feat we have achieved," said Manu Kumar Jain, Vice President, Xiaomi, and Managing Director, Xiaomi India.
This milestone has been achieved in the period starting Q3 2014 till July 2019, according to the International Data Corporation (IDC).
The company's Redmi A and Redmi Note series have been two of the most popular smartphone series in the country.
"I am extremely thankful to our 100 million smartphone users and we promise to keep working hard on delivering impeccable user experience across product, after sales and retail verticals," Jain added.
Xiaomi has been the leading smartphone brand in India for eight consecutive quarters, with a 28.3 per cent market share for Q2 2019 as per the IDC.
Redmi 6A and Redmi Note 7 Pro were the top two best-selling smartphones in the industry for Q2 2019.