Film star Akshay Kumar called it a "golden moment" for the country and Kareena Kapoor Khan, Taapsee Pannu and Vicky Kaushal among others wrote how proud India was of her achievement.
The 19-year-old wheelchair-bound shooter from Jaipur fired her way to the top of the podium in the R-2 women's 10m air rifle standing SH1 event.
Kumar took to Twitter and wrote Lekhara had hit the "bullseye" with her win.
"Congratulations #AvaniLekhara for hitting the bullseye and creating history by becoming the first Indian woman to win a #Paralympics gold medal Sports medal. What a debut!" the "BellBottom" actor wrote.
Kaushal took to Instagram and called Lekhara a "star".
"First ever Gold for India at Paralympics! Congratulations @avani.lekhara for this historic win. What a debut! What a star," the "Uri" actor wrote.
Abhishek Bachchan tweeted, "A gold-en moment for India! Hats off @AvaniLekhara on becoming the first Indian woman to win gold at #TokyoParalympics."
Actors Randeep Hooda, Dia Mirza and Rakul Preet Singh also congratulated the shooter.
Following Avani's win, two-time gold-winning javelin throw veteran Devendra Jhajharia clinched a third Paralympic medal, a silver this time, while discus thrower Yogesh Kathuniya also finished second as India surpassed its best ever medal tally at the Games.
Sundar Singh Gurjar also chipped in with a bronze, finishing behind Jhajharia in the men's javelin throw F46 final.
Neeraj Chopra, who recently won a gold at the Tokyo Olympics, wrote, "Devendra bhai sahab: you are such an inspiration to all of us! Congratulations on your 3rd #Paralympics medal! Many congratulations to Sundar bhai also for winning a Third place medal @DevJhajharia @SundarSGurjar."
Indian T20 women's team captain Harmanpreet Kaur wrote, "A spirited performance by our Indian athletes at the Paralympic Games. 👏 Congratulations: Avani Lekhara on becoming the 1st Indian woman to win🥇 Bhavina Patel, Nishad Kumar ,Devendra Jhajharia and Yogesh Khatuniya on winning🥈 Sundar Singh Gurjar and Vivek Kumar on winning.
IPL franchise Mumbai Indians also congratulated the winners.
Cricketer Suresh Raina wrote, "India’s Golden Girl @avanilekhara bull’s-eye shot. What an inspiring performance #Paralympics @pumacricket."
India opened its medal tally on Sunday with Bhavina Patel winning the first-ever silver medal in table tennis at the Paralympics. Nishad Kumar also won a silver in high jump, followed by a bronze by Vinod Kumar in discus throw.