William Randall Allen QC (June 29, 1919 – October 1, 1985) was a Canadian lawyer and politician who served as the Chairman of the Municipality of Metropolitan Toronto from 1962 to 1969.

During World War II, he enlisted with the Queen's York Rangers and attained the rank of captain, serving overseas in Britain and Europe.

His father, Robert Aloysius Allen, was an alderman and then a Liberal Member of Provincial Parliament representing Riverdale during the 1930s.

In 1950, William Allen entered municipal politics with his election as an alderman on Toronto city council, representing Riverdale in Ward 1.

While these municipalities continued to manage some local matters, Metropolitan Toronto assumed the responsibilities of more expensive programs, such as the TTC, police, and welfare.

After leaving politics, he served as President and CEO to several corporations and sat on the Board of Directors for Molson, Air Canada, York University, the Toronto Stock Exchange, and others.

He presided over the expansion of the subway network and continued with the expressway building program, which was cancelled after his exit from politics.