William R. Callahan (April 27, 1925 – January 1976) was a Democratic member of the Massachusetts House of Representatives.

He was a Malden resident who represented the 16th Middlesex district for one term, from 1971 to 1973.

Before serving in the state legislature, he was a member of the Malden Common Council for two years and the Malden City Council for 14 years.

He was a member of multiple organizations, including the Knights of Columbus and the Ancient Order of Hibernians.

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