The 1940 United States House of Representatives elections were elections for the United States House of Representatives to elect members to serve in the 77th United States Congress. They were held for the most part on November 5, 1940, while Maine held theirs on September 9. They coincided with President Franklin D. Roosevelt's re-election to an unprecedented third term. His Democratic Party narrowly gained seats from the opposition Republican Party, cementing their majority. However, the election gave firm control of the US House of Representatives and Senate to the New Dealers once again, as Progressives dominated the election.

The upswing in the economy that occurred following the Recession of 1937–38 encouraged voters that the New Deal plan had been working. This allowed the Democrats to stabilize their support.

1940 United States House of Representatives elections

, this is the last time the House of Representatives was made up of six parties.

1940 United States House of Representatives elections

Overall results

Source: Election Statistics - Office of the Clerk

Special elections

Many special elections were held. The elected winner would serve only the remainder of the incumbent Congress. Sorted by election date.

1940 United States House of Representatives elections

|-

! | Carl Mapes | | Republican | 1912 | | Incumbent died December 12, 1939.New member elected February 19, 1940.Republican hold.Winner was subsequently re-elected in November; see below. | nowrap |

|-

! | William A. Ashbrook | | Democratic | 19061920 1934 | | Incumbent died January 1, 1940.New member elected February 27, 1940.Republican gain.Winner was subsequently re-elected in November; see below. | nowrap |

|-

! | Chester C. Bolton | | Republican | 19281936 1938 | | Incumbent died October 29, 1939.New member elected February 27, 1940.Republican hold.Winner was subsequently re-elected in November; see below. | nowrap |

|-

! | Cassius C. Dowell | | Republican | 1936 | | Incumbent died February 4, 1940.New member elected March 5, 1940.Republican hold.Winner was subsequently re-elected in November; see below. | nowrap |

|-

! | George H. Heinke | | Republican | 1938 | | Incumbent died January 2, 1940.New member elected April 19, 1940.Republican hold.Winner did not run for re-election in November; see below. | nowrap |

|-

! | Clyde H. Smith | | Republican | 1936 | | Incumbent died April 8, 1940.New member elected June 3, 1940.Republican hold.Winner was subsequently re-elected in November; see below. | nowrap |

|-

! | W. Benjamin Gibbs | | Democratic | 1938 | | Incumbent died August 7, 1940.New member elected October 1, 1940.Democratic hold.Winner did not run for re-election in November; see below. | nowrap |

|-

! | William B. Bankhead | | Democratic | 1916 | | Incumbent died September 15, 1940.New member elected November 5, 1940.Democratic hold.Winner did not run for the next term; see below. | nowrap |

|-

! | John Andrew Martin | | Democratic | 19081912 1932 | | Incumbent died December 23, 1939.New member elected November 5, 1940.Democratic hold.Winner did not run for the next term; see below. | nowrap |

|-

! | William I. Sirovich | | 1926 | | Incumbent died December 17, 1939.New member elected November 5, 1940.Democratic hold.Successor also elected the same day to the next term; see below. | nowrap |

|-

! | Edward W. Curley | | 1935 (special) | | Incumbent died January 6, 1940.New member elected November 5, 1940.Democratic hold.Successor also elected the same day to the next term; see below. | nowrap |

|-

! | Wallace E. Pierce | | 1938 | | Incumbent died January 3, 1940.New member elected November 5, 1940.Republican hold.Successor also elected the same day to the next term; see below. | nowrap |

|-

! | Walter Chandler | | 1934 | | Incumbent resigned.New member elected November 5, 1940.Democratic hold.Successor also elected the same day to the next term; see below. | nowrap |

|}

Alabama

|-

! | Frank W. Boykin | | Democratic | 1935 | Incumbent re-elected. | nowrap |

|-

! | George M. Grant | | Democratic | 1938 | Incumbent re-elected. | nowrap |

|-

! | Henry B. Steagall | | Democratic | 1914 | Incumbent re-elected. | nowrap |

|-

! | Sam Hobbs | | Democratic | 1934 | Incumbent re-elected. | nowrap |

|-

! | Joe Starnes | | Democratic | 1934 | Incumbent re-elected. | nowrap |

|-

! | Pete Jarman | | Democratic | 1936 | Incumbent re-elected. | nowrap |

|-

! | William B. Bankhead | | Democratic | 1916 | | Incumbent died September 15, 1940.Democratic hold. | nowrap |

|-

! | John Sparkman | | Democratic | 1936 | Incumbent re-elected. | nowrap |