Christopher John Brennan (1 November 1870 – 5 October 1932) was an Australian poet and scholar.
Brennan was born in Sydney, to Christopher Brennan (d. 1919), a brewer, and his wife Mary Ann née Carroll (d. 1924), both Irish immigrants. His education took place at two schools in Sydney: he first attended St Aloysius' College, and after gaining a scholarship from Patrick Moran, he boarded at St Ignatius' College, Riverview. Brennan entered the University of Sydney in 1888, taking up studies in the Classics, and won a travelling scholarship to Berlin. There he met his future wife, Anna Elisabeth Werth; there, also, he encountered the poetry of Stéphane Mallarmé. About this time, he decided to become a poet. In 1893 Brennan's article "On the Manuscripts of Aeschylus" appeared in the Journal of Philology,
Brennan began forming a theory about the descent of Aeschylus' extant manuscripts in 1888. Returning to Australia, Brennan took up a position as a cataloguer in the public library, before being given a position at the University of Sydney. In 1914, he produced his major work, Poems: 1913. After Brennan's marriage broke up in 1922, he went to live with Violet Singer, the 'Vie' of his later poems, and, as a result of both his divorce and increasing drunkenness, he was removed from his position at the University in June 1925. The death of Singer in an accident left him distraught, and he spent most of his remaining years in poverty. Brennan died in 1932 from cancer.
Brennan influenced Australian writers of his own generation and many who succeeded him, including R. D. Fitzgerald, A.D. Hope, Judith Wright and James McAuley. In remembrance, the Fellowship of Australian Writers established the Christopher Brennan Award which is presented annually to an Australian poet, recognising a lifetime achievement in poetry.