It is thought that suicide bombers killed around 253 people and injured more than 500 at churches and hotels across Sri Lanka on Easter Sunday.
The 'Not In My Name' event was attended by more than 100 people this afternoon (Thursday) and was hosted by Reverend Hilary Barber, Vicar of Halifax.
He gave a speech at the event, while Halifax MP Holly Lynch, Divisional Commander of West Yorkshire Police Dickie Whitehead, Mayor of Calderdale Marcus Thompson, Leader of Calderdale Council Tim Swift and Nadeem Mir, of the Council of Mosques, also spoke before there was a minute's silence and prayers.
Halifax MP Holly Lynch said: "I had the opportunity to visit Sri Lanka with a cross-party delegation in 2016, and we met with some of those hospital workers who I know will have been on the front-line and responding to the attacks.
"Yet again, we're having to all come together to say that these horrible, heinous acts will not be tolerated.
"The way we overcome that is to be united, talk to each other and overcome it together.
"I've no doubt Sri Lanka will overcome this in the way we've seen New Zealand had to do, with international support."
On the significance of the event at Halifax Minster, Ms Lynch said: "You've got members from all across Calderdale coming here together at the Minster, and it's our opportunity in Halifax to unite and show solidarity with the people of Sri Lanka.
"We appreciated international support when we were the victims of terror not so long ago, sit's a chance for us to show that solidarity with Sri Lanka, and remember that sadly we have lost eight British lives, including children, in these atrocious bombings.
"Terror will never win, we will come together to do what terrifies them, and that's talk to each other.
"Using diplomacy, democracy, we'll all build a bright future together and not allow violence to fill that void."
Nadeem Mir, of the Council of Mosques, said: "It was just horrific. It's not been two, three months since New Zealand, and we all come together then in solidarity.
"And we're back again talking about the same things - hatred, how do we tackle that, how do we get into the psyche of these individuals that feel it's OK to take the lives of innocent people?
"We can't live in a society when you're going into a religious establishment, a place for peace, and people feel it's OK to take the lives of other people?
"There's a lot more work we need to do. We've got to understand what drives them, and tackle it at a much earlier stage than trying to be reactive.
"We've come to console those that have lost people, pay our condolences to the families and to say 'not in our name'.
"We've got a problem, and we've got to do more to try and address it an earlier stage.
"Every community's got a part to play."
Reverend Hilary Barber, Vicar of Halifax, said: "There were about 350 people in the Minster on Sunday morning, and had that happened here, the whole congregation would have been wiped out.
"I got a phone call on Monday morning from a friend of mine who's a working peer in the House of Lords, to say that his sister and her husband had been killed in the attacks.
"So it makes it very real. I went to Old Trafford on Wednesday to watch the Manchester derby, and there were armed police everywhere, and people in fear that a large crowd means that there is going to be trouble.
"We live in a very vulnerable world at the moment."
When asked what message he wanted the event to send out, the Rev Barber said: "We care and we want to make the world a better place for children to play and for people to grow old, and here in Calderdale, we're going to do something about it, and make sure that we make society a kinder place, and a more resilient place.
"And that we look out for one another, and that when there are hate crimes and bigotry, and racism, that we stand up to it, and we won't have it in our own backyard."