Hashtags MumbaiTerrorAttack were trending with 57.5K tweets, #MumbaiAttacks with 23.1K tweets, #2611attack with 7692 tweets, and #HemantKarkare with 2444 tweets.
Twitter users posted pictures of the terror attack along with pictures of security personnel who fought against the terrorists and those who were killed in action.
At least 166 people, including foreigners, were killed when 10 Lashkar-e-Taiba terrorists attacked five major sites in Mumbai 11 years ago.
Union Minister of State Babul Supriyo tweeted: "Tributes to our brave security personnel who sacrificed their lives for our security. Let us vow to stand united against terrorism and be prepared to defeat cowardice acts like these. #2611attack#MumbaiAttacks"
US Ambassador to India, Ken Juster, wrote on @USAmbIndia to remind that November 26 marks the 11th anniversary of the Mumbai terror attack.
"As we remember and honor the victims and stand side-by-side with the people of India, we must remain strong and united in the face of terrorism, and more determined than ever to defeat it. #2611Attack," he posted.
Delhi Deputy Chief Minister Manish Sisodia said: "Heartfelt tributes to the valiant martyrs of the #2611Attack on the 11th anniversary of the tragedy in Mumbai. We will never forget their sacrifice ? their sacrifice unites us against the forces which intend to divide us with terror."
Industrialist Anand Mahindra posted pictures and posted a couplet. He commented: "On 26/11 there is no other subject to tweet about. We remember their battle; we remember their courage; we remember our debt to our heroes..."
Bollywood actress Koena Mitra said: "Paying tribute to the valour and sacrifice of our heroes of 26/11. Condolences to the families who lost their loved ones."
( With inputs from IANS )