| Senator | Lifespan | Party [1] | Prov. | Entered | Left | Appointed by | Left due to | For life? |
|---|---|---|---|---|---|---|---|---|
| John Abbott | 1821–1893 | L | QC | 12 May 1887 | 30 October 1893 | Macdonald | Death | Y |
| Michael Adams | 1845–1899 | C | NB | 7 January 1896 | 1 January 1899 | Bowell | Death | Y |
| Willie Adams | 1934–present | L | NT NU | 5 April 1977 September 2, 1999 | September 2, 1999 22 June 2009 | Trudeau, P. | Retirement | |
| Charles Adler | 1954–present | MB | 16 August 2024 | — | Trudeau, J. | — | ||
| James Cox Aikins | 1823–1904 | LC | ON | 23 October 1867 7 January 1896 | 30 May 1882 6 August 1904 | Royal proclamation Bowell | Resignation Death | Y |
| John Black Aird | 1923–1995 | L | ON | 10 November 1964 | 28 November 1974 | Pearson | Resignation | Y |
| George Alexander | 1814–1903 | C | ON | 30 May 1873 | 29 May 1891 | Macdonald | Resignation | Y |
| George William Allan | 1822–1901 | C | ON | 23 October 1867 | 24 July 1901 | Royal proclamation | Death | Y |
| William Johnston Almon | 1816–1901 | LC | NS | 15 April 1879 | 18 February 1901 | Macdonald | Death | Y |
| Doris Margaret Anderson | 1922–2022 | L | PE | 21 September 1995 | 5 July 1997 | Chrétien | Retirement | |
| John Hawkins Anderson | 1805–1870 | L | NS | 23 October 1867 | 24 December 1870 | Royal proclamation | Death | Y |
| Margaret Dawn Anderson | 1967–present | NT | 12 December 2018 | — | Trudeau, J. | — | ||
| Margaret Jean Anderson | 1915–2003 | L | NB | 23 March 1978 | 7 August 1990 | Trudeau, P. | Retirement | |
| Raynell Andreychuk | 1944–present | C | SK | 11 March 1993 | 14 August 2019 | Mulroney | — | |
| Auguste-Réal Angers | 1837–1919 | C | QC | 16 December 1892 | 10 June 1896 | Thompson | Resignation | Y |
| W. David Angus | 1937–present | C | QC | 10 June 1993 | 21 July 2012 | Mulroney | Retirement | |
| Thomas Dickson Archibald | 1813–1890 | LC | NS | 23 October 1867 | 18 October 1890 | Royal proclamation | Death | Y |
| Hazen Argue | 1921–1991 | L | SK | 24 February 1966 | 2 October 1991 | Pearson | Death | |
| Joseph-François Armand | 1820–1903 | C | QC | 23 October 1867 | 1 January 1903 | Royal proclamation | Death | Y |
| David Arnot | 1952–present | SK | 29 July 2021 | — | Trudeau, J. | — | ||
| Joseph-Octave Arsenault | 1828–1897 | C | PE | 18 February 1895 | 14 December 1897 | Bowell | Death | Y |
| James Arthurs | 1866–1937 | C | ON | 20 July 1935 | 7 October 1937 | Bennett | Death | Y |
| Walter Aseltine | 1886–1971 | C | SK | 30 December 1933 | 31 March 1971 | Bennett | Resignation | Y |
| Martial Asselin | 1924–2013 | PC | QC | 1 September 1972 | 7 August 1990 | Trudeau, P. | Resignation | |
| Salma Ataullahjan | 1952–present | C | ON | 9 July 2010 | — | Harper | — | |
| Norman Atkins | 1934–2010 | PC | ON | 2 July 1986 | 27 June 2009 | Mulroney | Retirement | |
| Réjean Aucoin | 1955–present | NS | 31 October 2023 | — | Trudeau, J. | — | ||
| Michèle Audette | 1971–present | QC | 29 July 2021 | — | Trudeau, J. | — | ||
| Jack Austin | 1932–present | L | BC | 19 August 1975 | 2 March 2007 | Trudeau, P. | Retirement | |
| Allen Bristol Aylesworth | 1854–1952 | L | ON | 11 January 1923 | 13 February 1952 | King | Death | Y |