Francis "Frank" X. McDermott (October 15, 1924 – December 15, 2011) was an American Republican Party politician who served in both houses of the New Jersey Legislature.
McDermott was born in New York City in 1924. He received a Bachelor of Arts from Columbia College, a Juris Doctor from Columbia Law School, and a Master of Public Administration and Master of Laws from New York University. He was admitted to practice as an attorney in New York and New Jersey. He settled in Westfield, New Jersey with his wife, the former Patricia Keogh.
In 1955 he served as New Jersey delegate to the White House Conference on Education. In 1963 he was elected to the New Jersey General Assembly from Union County for the first time. He served as assistant majority leader in 1965 and minority leader in 1966.
In 1967 McDermott was elected to the New Jersey Senate. The following year he served as majority leader. In 1969 he was selected as Senate President, serving as acting governor in the absence of Governor Richard J. Hughes. Also in 1969, he was an unsuccessful candidate for the Republican nomination for Governor of New Jersey. He lost the Republican primary to William T. Cahill, also finishing behind U.S. Rep. Charles W. Sandman, Jr. and State Sen. Harry L. Sears. He was Senate President pro tempore from 1970 to 1973.