This article is a list about the mayors of Longueuil, Quebec and the municipalities that were folded into Longueuil to make the current city.
Before 1961, seven separate communities existed to form what is today known as Longueuil. They merged over the following decades, and Longueuil reached its current state.
This section lists a series of mergers involving Longueuil. In italic is the surviving municipality.
On January 28, 1961, these communities merged, keeping Longueuil's namesake:
In 1969, Longueuil merged again with another neighbouring city:
In October, 1971, neighbouring Saint-Hubert had a merger as well:
On January 1, 2002, Longueuil and seven other south shore municipalities merged:
On January 1, 2006, four of the municipalities previously merged in 2002 voted to secede from Longueuil:
Therefore, Longueuil is currently composed of:
| Isidore Hurteau | 1848 | 1850 | |
| Charles Sabourin | 1850 | 1853 | |
| 1853 | 1861 | ||
| André Trudeau | 1861 | 1862 | |
| 1862 | 1870 | ||
| Isidore Hurteau (again) | 1870 | 1872 | |
| Augustin Pierre Jodoin | 1872 | 1876 | |
| Isidore Hurteau (again) | 1876 | 1878 | |
| vacant | 1878 | 1880 | |
| Joseph Vincent | 1880 | 1881 | |
| Charles Bourdon | 1881 | 1882 | |
| Bruno Normandin | 1882 | 1886 | |
| Pierre E. Hurteau | 1886 | 1887 | |
| Louis E. Morin | 1887 | 1889 | |
| Pierre Brais | 1889 | 1891 | |
| Bruno Normandin (again) | 1891 | 1892 | |
| Louis E. Morin (again) | 1892 | 1893 | |
| Ovide Dufresne Jr. | 1893 | 1896 | |
| Michel Viger | 1896 | 1898 | |
| 1898 | 1902 | ||
| Victor Pigeon | 1902 | 1904 | |
| Édouard C. Lalonde | 1904 | 1906 | |
| Bruno Normandin (again) | 1906 | 1908 | |
| 1908 | 1912 | ||
| Henri St-Mars | 1912 | 1915 | |
| 1915 | 1925 | ||
| L. J. Émilien Brais | 1925 | 1933 | |
| Alexandre Thurber (again) | 1933 | 1935 | |
| 1935 | 1966 | ||
| 1966 | 1969 | ||
| Roland Therrien | 1969 | 1969 | |
| Marcel Robidas (again) | 1969 | 1982 | |
| 1982 | 1987 | ||
| Florence Mercier | 1987 | 1987 | |
| 1987 | 1994 | ||
| 1994 | 2001 | ||
| 2001 | 2005 | ||
| Claude Gladu (again) | 2005 | 2009 | |
| 2009 | 2017 | ||
| 2017 | 2021 | ||
| 2021 | incumbent |
| John Smillie | 1906 | 1910 | |
| Napoléon Labonté | 1910 | 1912 | |
| John Smillie | 1912 | 1916 | |
| Edmond Hardy | 1916 | 1924 | |
| David McQuaid | 1924 | 1932 | |
| Henry Hamer | 1932 | 1936 | |
| Clément Patenaude | 1936 | 1938 | |
| Harry T. Palmer (resigned) | 1938 | 1939 | |
| James Brindley (resigned) | 1939 | 1942 | |
| Robert Gault Keers | 1942 | 1948 | |
| Édouard Richer | 1948 | 1950 | |
| Aimé Lefebvre | 1950 | 1952 | |
| Marcel Salette | 1952 | 1958 | |
| Sylva Charland | 1958 | 1961 |
| Joseph-Rémi Goyette | 1947 | 1949 | |
| René Prévost | 1949 | 1954 | |
| Hector Desmarchais | 1954 | 1955 | |
| Julien Lord | 1955 | 1957 | |
| Joseph-Louis Chamberland | 1957 | 1960 | |
| Léo-Aldéo Rémillard | 1960 | 1963 | |
| Jean-Paul Tousignant (interim) | 1963 | 1963 | |
| Charles Labrecque (interim) | 1963 | 1963 | |
| Jean-Paul Vincent | 1963 | 1966 | |
| Roland Therrien | 1966 | 1969 |
| J. W. Gendron | 1947 | 1949 | |
| Lucien Tapin | 1949 | 1953 | |
| Édouard Charruau | 1953 | 1957 | |
| Paul Provost | 1957 | 1962 | |
| Henri Cyr | 1962 | 1963 | |
| Alexandre Girard | 1963 | 1965 | |
| Gérard Philipps | 1965 | 1971 |
| André Sainte-Marie | 1861 | 1862 | |
| Louis Brosseau | 1862 | 1866 | |
| Jean-Baptiste Sainte-Marie | 1866 | 1868 | |
| Laurent Benoît | 1868 | 1870 | |
| François David | 1870 | 1881 | |
| Toussaint Brosseau | 1881 | 1881 | |
| Joseph Paré | 1881 | 1890 | |
| Wilfrid Tremblay | 1890 | 1897 | |
| Alexis Tremblay | 1897 | 1898 | |
| Émerie Brosseau | 1898 | 1901 | |
| Pierre-Élie Sainte-Marie | 1901 | 1905 | |
| Aimé Guertin | 1905 | 1907 | |
| Moïse Brosseau | 1907 | 1908 | |
| Adelphis Lareau | 1908 | 1909 | |
| Noël Bouthillier | 1909 | 1910 | |
| Joseph Paré Jr. | 1910 | 1915 | |
| Flavien Moquin | 1915 | 1916 | |
| Arthur Barré | 1916 | 1925 | |
| Henri Rocheleau | 1925 | 1927 | |
| Antoine-Morille Labelle | 1927 | 1928 | |
| Anatole Lavoie | 1928 | 1931 | |
| André Latour | 1931 | 1937 | |
| Hubert Guertin | 1937 | 1949 | |
| Samuel Robinson | 1949 | 1955 | |
| Gérard Payer | 1955 | 1961 | |
| Euchariste Harvey | 1961 | 1963 | |
| Norman Litchfield | 1963 | 1968 | |
| Aldas Boileau | 1968 | 1976 | |
| Bernard Racicot | 1976 | 1984 | |
| Guy Desgroseillers | 1984 | 1988 | |
| Pierre D. Girard | 1988 | 1996 | |
| Michel Latendresse | 1996 | 2001 |
| Henri Sicotte | 1949 | 1952 | |
| Albert Bélanger | 1952 | 1954 | |
| Jean Baribeau | 1954 | 1967 | |
| André Charpentier | 1967 | 1977 | |
| Michel Sicotte | 1977 | 1981 | |
| Louise Gravel | 1981 | 1993 | |
| Guy Talbot | 1993 | 2001 |
| W.J. Murray | 1911 | 1913 | |
| R. C. Chalmers | 1915 | 1918 | |
| R. J. Walker | 1918 | 1922 | |
| C. D. Campbell | 1922 | 1926 | |
| R. J. Walker | 1927 | 1928 | |
| H. W. Clark | 1928 | 1930 | |
| E. A. Nightingale | 1930 | 1932 | |
| S. I. Coote | 1932 | 1940 | |
| E. F. Blackburn | 1940 | 1942 | |
| A. G. Cobb | 1942 | 1946 | |
| A. Perras | 1946 | 1948 | |
| J. C. Plante | 1948 | 1953 | |
| L. Galetti | 1953 | 1967 | |
| Maurice King | 1967 | 1978 | |
| Stephen Olynyck | 1978 | 1994 | |
| Marc Duclos | 1994 | 2001 |