CBCNews.ca and CBC News Network are carrying his address live.
"When you are in Canada, you are home," Harper told the Aga Khan in his introduction before members of both the House of Commons and the Senate.
Harper spoke of the deep ties between the Imamat — the entity that represents the succession of Imams — and Canada, especially with regards to diversity.
"Canadians are strongest when we have the support of those who share our values."
Earlier in the morning, the Aga Khan was greeted on the Hill and then met privately with Harper.
The 77-year-old Aga Khan is hereditary spiritual leader of the world's 15 million Shia Ismaili Muslims.
He is a regular visitor to Canada, with his most recent trip coming last November following visits in 2008 and 2010.
The Aga Khan was granted honorary Canadian citizenship during the 2010 visit.
The Aga Khan became the 49th Imam of the Shia Ismaili Muslims in 1957, when he succeeded his grandfather.