The Twelfth of July celebrations generate at least £6m for the Northern Ireland economy, says the Orange Order.
Orange Order is the largest Protestant organisation in NI
It has carried out a survey on what members and followers spend on food, transport, clothing and hotels.
The 12 July parades commemorate Protestant Prince William of Orange's 1690 Battle of the Boyne victory over Catholic King James II.
Discussions have been held between the Tourist Board and Orange Order about promoting the events.
Order Order grand secretary Drew Nelson said they wanted to work with the tourist board to market the day.
"During the last Twelfth of July celebrations we did a survey of our membership and we asked them what type of money they had spent on things like transport, meals, clothing, souvenirs and accommodation," he said.
"We extrapolated that out across the whole institution and that's how we came to the figure (of £6m).
"He said the money spent by orangemen contributed to the local economy.
"One of the things that surprised us was the amount of money spent on accommodation by people coming into the province.
'Unique and diverse'
"Mr Nelson said he recognised the costs to the economy caused by the stand-offs and violence at the controversial annual Orange Order Drumcree in County Armagh.
"We understand for people to see that, but the world has moved on and the Orange Order is moving on," he said.
"We want to be looking forward and not back."
Phillip Pentland, industry development director with the Tourist Board, said it wanted to promote Northern Ireland's "unique and diverse culture".
"There is a big difference, of course, between culture and the expression of culture , and cultural tourism," he said.
"Of course, it is cultural tourism that we seek to promote in terms of growing tourism for Northern Ireland."
The Orange Order is the largest Protestant organisation in Northern Ireland with at least 75,000 members, some of them in the Republic of Ireland.
Its origins date from the 17th century battle for supremacy between Protestantism and Catholicism. Prince William of Orange, originally of the Netherlands, led the fight against Catholic King James.