Prime Minister Narendra Modi condemned the "serial terrorist attacks" in a government statement. "Terming them as cold-blooded and pre-planned barbaric acts, he pointed out that these attacks were another grim reminder of the most serious challenge posed to the entire humanity by terrorism in our region and the entire world," the statement added.
Pakistan's leader Imran Khan offered his "profound condolences" to Sri Lanka.
"Strongly condemn the horrific terrorist attack in Sri Lanka on Easter Sunday resulting in precious lives lost & hundreds injured," he tweeted.
British Prime Minister Theresa May described the attacks as "truly appalling".
"The acts of violence against churches and hotels in Sri Lanka are truly appalling, and my deepest sympathies go out to all of those affected at this tragic time," she tweeted.
US President Donald Trump tweeted: "Heartfelt condolences from the people of the United States to the people of Sri Lanka on the horrible terrorist attacks on churches and hotels.
"We stand ready to help!"
"Terrible reports from Sri Lanka about bloody attacks on hotels and churches on this Easter Sunday," Dutch Prime Minister Mark Rutte tweeted after initial news of the attacks.
"Thoughts are with the victims and their relatives."
Pope Francis expressed his sadness over the attacks during his traditional Easter address at the Vatican.
"I want to express my affectionate closeness with the Christian community, attacked while it was at prayer, and to all the victims of such cruel violence," he said.
The Catholic Church in Jerusalem had said in an earlier statement: "We pray for the souls of the victims and ask for speedy recovery of the injured, and ask God to inspire the terrorists to repent of their killing and intimidation."
Prime Minister Scott Morrison said in a statement: "At this time as Easter Sunday draws to a conclusion here in Australia, our heart goes out to those Christians and all of those other innocents who have been slaughtered today in this horrific terrorist attack."
"I would like to reassert that Russia has been and remains a reliable partner of Sri Lanka in combating the threat of international terrorism," Vladimir Putin said in a Kremlin statement.
"Prime Minister Benjamin Netanyahu expresses in the name of Israel's citizens deep shock over the murderous attacks against innocent civilians in Sri Lanka," a government statement said.