The former finance minister died suddenly last week of an apparent heart attack in his Ottawa home. His unexpected passing has left Ottawa reeling in an outpouring of grief that cut across party lines.
Prime Minister Stephen Harper, NDP Leader Tom Mulcair and Liberal Leader Justin Trudeau will be among those at St. James Cathedral on Wednesday, along with a roster of Conservative cabinet ministers.
Both Harper and Mulcair fought tears last week when news of the 64-year-old Flaherty's death reverberated on Parliament Hill. The longtime finance minister, a popular figure in international financial circles, had retired less than a month earlier.
Flags on the Hill remain at half-mast. Hundreds of Canadians, meantime, have been signing an online book of condolences to pay tribute to Flaherty.
A typical message thanked the longtime Conservative for his lifetime of public service.
Rob Merrifield, a Tory Alberta MP, posted a message on his website commemorating Flaherty, describing the former member of the Ontario legislature as a man who loved to laugh and have a good time.