The monarch of the oil-rich country who sought to modernize the ultraconservative Muslim kingdom died Friday at the age of 90.
A royal court statement said Abdullah's 79-year-old half-brother, Prince Salman, would become the new Saudi leader.
In a statement, Harper said Abdullah was a "strong proponent of peace" in the Middle East.
Harper said the monarch also undertook a range of important economic, social, education, health, and infrastructure initiatives in his country.
Harper said he met King Abdullah in Toronto during a G-20 summit and found him to be "passionate about his country, development and the global economy.
Abdullah was selected as crown prince in 1982 on the day his half-brother Fahd ascended to the throne. He became de facto ruler in 1995 when a stroke incapacitated Fahd and became king in 2005.
— with files from The Associated Press
Also on HuffPost