|Member of the Australian Parliament|
8 February 1911 - 19 December 1931
15 September 1934 - 31 October 1949
|Died||6 November 1950 (aged 76–77)|
|Political party||Australian Labor Party|
|Spouse(s)||Cecilia Mary O'Donnell|
|Relations||Tom Brennan (brother)|
|Alma mater||University of Melbourne|
Francis (Frank) Brennan (1873 - 6 November 1950) was an Australian lawyer and Australian Labor Party politician.
Brennan was born at Upper Emu Creek near Bendigo, Victoria and was a younger brother of Tom Brennan, later an assistant minister in the conservative Lyons government. He studied law at the University of Melbourne and achieved an LL.B. in 1901. A prominent lay figure in Melbourne Catholicism, he established a legal business specialising in union cases. He joined the Labor Party in 1907 and unsuccessfully contested Bendigo in 1910, but won Batman at a by-election in 1911. In 1913 he married Cecilia Mary O'Donnell.
Following Labor's election win during 1929, Brennan became Attorney-General in the Scullin Ministry, but was not particularly effective in this role. In any event, he lost his seat in the 1931 election as a result of the swing against Labor, which came about because of the Great Depression and the resultant split in the Labor Party. Although Brennan had gone into the election holding Batman with a comfortably safe majority of 25.8 percent, he was defeated by United Australia Party challenger Samuel Dennis on an unheard-of swing (the biggest in Australian electoral history until that time) of 26.6 percent. He recovered Batman in a rematch against Dennis in the 1934 election and held it until his retirement in 1949.