Thomas Dyer, American lawyer and politician, 18th Mayor of Chicago (died 1862)

Thomas Dyer served as mayor of Chicago, Illinois (1856–1857) for the Democratic Party. He also served as the founding president of the Chicago Board of Trade.

The mayor of Chicago is the chief executive of city government in Chicago, Illinois, the third-largest city in the United States. The mayor is responsible for the administration and management of various city departments, submits proposals and recommendations to the Chicago City Council, is active in the enforcement of the city's ordinances, submits the city's annual budget and appoints city officers, department commissioners or directors, and members of city boards and commissions.