More than 60 percent of Orange Order members believe that "most Catholics are IRA sympathizers."
The startling views are contained in a new book and are based on responses of 1,500 members of the order from across Northern Ireland.
The book, "Loyal to the Core? Orangeism and Britishness in Northern Ireland," also notes that nine out of 10 Orangemen think Protestants are discriminated against.
One of the authors of the book, Professor Jon Tonge from Liverpool University, said the findings were "disturbing."
Only six percent of respondents said they would be in favor of one of their children marrying a Catholic.
"Only nine percent of marriages are mixed here (Northern Ireland), so in that sense the Orange Order is not that far removed," said Mr. Tonge.
He said the book was the first of its kind and had the full backing of the Orange Order.
"They wanted a full and frank survey. We did offer concessions, but in the end they chose not to hold anything back," he said.
"They wanted a warts and all survey."
In recent months, the Orange Order has come under criticism after it took disciplinary proceedings against Ulster Unionist leader Tom Elliott and fellow party MLA Danny Kennedy for attending the funeral of Catholic police officer Ronan Kerr, who died after a bomb exploded under his car near Omagh in County Tyrone in April of this year.
Orange Order rules bar members from attending Catholic Masses.
