The Dean of the U.S. House of Representatives is the longest-serving (in consecutive terms) member of the United States House of Representatives, at present John Dingell.

The only duty customarily associated with this position is to swear in a Speaker of the House when he is elected; unlike the Father of the House in the United Kingdom House of Commons, he does not preside over the election but comes forward on the floor to administer the oath to the Speaker-elect, and this presumably dates no further back than 1961 when the two posts last ceased to be held by the same person.

Seniority having other privileges attached, the Dean is usually allotted some of the most desirable office space, and (though a party caucus occasionally deems otherwise) either the chairmanship of an influential committee (if a member of the majority party), or the position of ranking minority member of one.

It is unclear when the position first achieved concrete recognition, though the seniority system and increasing lengths of service emerged in the early 20th century. The first two six-term members of the United States Senate, Ellison DuRant Smith and Kenneth McKellar, were first elected in 1908 and 1916 respectively. As late as 1924, Frederick H. Gillett was Dean, and also Speaker, before becoming a Senator himself; modern Deans move into their positions so late in their careers that a move to the Senate is highly unlikely.

The Deanship can change hands unexpectedly; in the 1952 election, Adolph J. Sabath became the first Representative elected to a 24th term, breaking the record of 23 terms first set by former Speaker Joseph Gurney Cannon, whose service had been discontinuous whereas Sabath's was not. North Carolina's Robert L. Doughton had not contested that election, as he was retiring at the age of 89 years and two months (a House age record broken only in 1998 by Sidney R. Yates, though Claude Pepper, who died early in his final term in 1989, holds the record for oldest winner of a House election). However, Sabath died before the new term began, and Doughton was Dean for the old term's final months, before Speaker Sam Rayburn became Dean in the new Congress.

More recently, Texas Democrat Jack Brooks was defeated for reelection in the year he was expected to succeed Jamie L. Whitten as Dean.

Deans of the U.S. House of Representatives since 1855

Years as Dean are followed by name, party, state, and start of service in Congress.

• ????-March 1855 Linn Boyd D-Kentucky (March 4, 1839)
• March 1855-March 1859 George Washington Jones D-Tennessee (March 4, 1843)
• March 1859-March 1863 John S. Phelps D-Missouri (March 4, 1845)
• March 1863-March 1869 Elihu B. Washburne W-Illinois (March 4, 1853)
• March 1869-March 1875 Henry L. Dawes R-Massachusetts (March 4, 1857)
• March 1875-January 1890 William D. Kelley R-Pennsylvania (March 4, 1861)
• January 1890-April 1890 Samuel J. Randall D-Pennsylvania (March 4, 1863)
• April 1890-March 1891 tie Joseph G. Cannon R-Illinois, Roger Q. Mills D-Texas, James H. Blount D-Georgia and Richard P. Bland D-Missouri (each March 4, 1873)
• March 1891-March 1892 tie Roger Q. Mills D-Texas, James H. Blount D-Georgia and Richard P. Bland D-Missouri (each March 4, 1873)
• March 1892-March 1893 tie James H. Blount D-Georgia and Richard P. Bland D-Missouri (both March 4, 1873)
• March 1893-March 1895 Richard P. Bland D-Missouri (March 4, 1873)
• March 1895-March 1897 David B. Culberson D-Texas (March 4, 1875)
• March 1897-September 1899 Thomas B. Reed R-Maine (March 4, 1877)
• September 1899-March 1912 Harry H. Bingham R-Pennsylvania (March 4, 1879)
• March 1912-December 1914 Sereno E. Payne R-New York (March 4, 1889)
• December 1914-April 1918 William A. Jones D-Virginia (March 4, 1891)
• April 1918-March 1919 tie, Henry Allen Cooper R-Wisconsin and Frederick H. Gillett R-Massachusetts (both March 4, 1893)
• March 1919-March 1925 Frederick H. Gillett (see above; he was also Speaker for these years)
• March 1925-May 1928 Thomas S. Butler R-Pennsylvania (March 4, 1897)
• May 1928-March 1933 Gilbert N. Haugen R-Iowa (March 4, 1899)
• March 1933-April 1934 Edward W. Pou D-North Carolina (March 4, 1901)
• April 1934-November 1952 Adolph Joachim Sabath D-Illinois (March 4, 1907)
• November 1952-January 1953 Robert L. Doughton D-North Carolina (March 4, 1911)
• January 1953-November 1961 Sam Rayburn D-Texas (March 4 1913) (also Speaker from 1955)
• November 1961-January 1965 Carl Vinson D-Georgia (November 3, 1914)
• January 1965-January 1973 Emanuel Celler D-New York (March 4, 1923)
• January 1973-March 1976 Wright Patman D-Texas (March 4, 1929)
• March 1976-January 1979 George H. Mahon D-Texas (January 3, 1935)
• January 1979-January 1995 Jamie L. Whitten D-Mississippi (November 4, 1941)
• January 1995-present John Dingell D-Michigan (December 13, 1955)

Kelley, Randall, Bingham, Payne, Jones, Cooper, Butler, Pou, Sabath, Rayburn, and Patman died in office.

Vinson, Whitten, and Dingell entered the House to fill unexpired terms.