The country entered a three-day mourning period yesterday following the attack in a park in Lahore, believed to be carried out by a suicide bomber.
The 18-year-old Nobel Prize winner, who lives in Birmingham, said: “I am devastated by the senseless killing of innocent people in Lahore.
“My heart goes out to the victims and their families and friends. I condemn this attack in the strongest possible terms.”
She called for Pakistan and the world to stand together, adding: “Every life is precious and must be respected and protected.”
More than 300 were injured in the attack, many seriously, after a device was detonated near children’s rides while families celebrated Easter.
A breakaway Pakistani faction of the Taliban claimed responsibility for the carnage and said it had deliberately targeted the Christian community.
However, most of those killed were Muslims — with 14 having been identified as Christians, according to Lahore Police Superintendent Mohammed Iqbal.
British prime minister David Cameron, who used his Easter message to urge Britons of all faiths to stand up for Christian values, said the attack shocked him.
“My thoughts are with the families and friends of the victims. We will do what we can to help,” Mr Cameron posted on his Twitter feed.
Labour leader Jeremy Corbyn said: “My thoughts are with the victims and the family of the victims of the horrific attack in Lahore.”
Facebook founder Mark Zuckerberg has spoken out against the “fear and distrust” spread by the recent wave of terror attacks — and called for love and empathy to combat them.
The tech entrepreneur said atrocities in Belgium, Pakistan, and Turkey were all designed to sow seeds of hatred between different communities.
Writing on his Facebook page, he wrote: “Each of these attacks was different, but all had a common thread: they were carried out with a goal to spread fear and distrust, and turn members of a community against each other.
“I believe the only sustainable way to fight back against those who seek to divide us is to create a world where understanding and empathy can spread faster than hate, and where every single person in every country feels connected and cared for and loved.”
At least 70 people were killed when a Taliban splinter group detonated a bomb in Lahore, Pakistan, on Easter Sunday.