Wilbert Ross Thatcher (24 May 1917–22 July 1971) was the tenth premier of Saskatchewan, Canada, serving from 2 May 1964 to 30 June 1971.

W. Ross Thatcher

Rank:	10th
Term of Office:	2 May 1964– 30 June 1971
Predecessor:	Woodrow S. Lloyd
Successor:	Allan Blakeney
Date of Birth:	24 May 1917
Date of Death:	22 July 1971
Spouse:	Peggy Thatcher
Profession:	businessman, politician
Political Party:	Liberal

Thatcher was a Moose Jaw-based businessman who developed an interest in politics shortly after the birth of his son, Colin Thatcher, in 1938. He joined the Moose Jaw Young Liberal Association and was soon elected an alderman of the city. In 1941, he switched parties to the CCF and was elected to Parliament four years later. In 1955, he left the CCF and sat out his term as an Independent MP before running unsuccessfully for the Liberal Party of Canada in the 1957 federal election.

Having switched to provincial politics, he led the Liberal Party of Saskatchewan to victory in the 1964 provincial election, defeating the New Democratic Party, which had governed the province since the 1944 election.

Thatcher was elected to the Legislative Assembly of Saskatchewan,and became Premier of the province.

Despite the 'Liberal' label, Thatcher's government was considered to be very right wing for its time, and Thatcher often clashed with the federal Liberal governments of Lester Pearson and Pierre Trudeau.

Thatcher's government was defeated by the NDP in the June 1971 election.

On 22 July 1971, Thatcher died in his sleep, apparently as a result of complications from a heart condition. His daughter-in-law, JoAnn Thatcher, later claimed she suspected the death was a suicide, though this has never been formally substantiated.

Ross Thatcher was the father of Colin Thatcher, a Conservative minister in the Saskatchewan cabinet in the 1980s prior to being charged and convicted of murdering his wife.