Robert Greig Davidson (21 July 1875 – 3 August 1948) was a Liberal party member of the House of Commons of Canada. He was born in Sherbrooke, Quebec and became a farmer.
Davidson attended high school in Sherbrooke and then St. Charles Borromeo College in Charlesbourg. He became a trustee of Stanstead Wesleyan College and director of the Western Townships Agricultural Association.
He was first elected to Parliament at the Stanstead riding in the 1935 general election.
He was re-elected for a second term in 1940. The Supreme Court, on appeal, annulled the election, because of corrupt practices arising from the buying of votes with whiskey and money. That ruling was also the first time the Supreme Court had set aside a lower court decision with respect to an election verdict. The matter had to be referred to the House Privileges and Elections Committee for a recommendation as to how to proceed. The committee would not report until May 1943, clearing the way for the byelection to be held.
Davidson attempted to return to office in the byelection held August 9, 1943, but was defeated by the Bloc Populaire candidate Joseph-Armand Choquette.