The Hon. Patrick McMahon Glynn KC (25 August 1855 - 28 October 1931) was a former Attorney General of Australia and Minister for External Affairs.

Born in Gort, County Galway and educated at Trinity College, Dublin, Glynn graduated with a BA and LLB, and was the medallist for Oratory at the Law Students Debating Society of Ireland in 1880. The same year saw Glynn immigrate to Australia, where he gained work as a journalist and Barrister prior to his election to the South Australian House of Assembly as the member for Light in 1887. Defeated in 1890, Glynn returned to South Australian colonial politics in 1895 as the member for North Adelaide and in his re-election in 1897, became the first person to be elected in Australia under adult suffrage.

Glynn was a member of the Convention that framed the Australian Commonwealth constitution in 1897-98 and was elected in 1901 to the inaugural federal parliament as a Commonwealth Liberal Party representative for South Australia. At the 1903 election, Glynn was returned unopposed as the member for Angas . He would also be returned unopposed in 1910, 1913 and 1914 before losing his seat at the 1919 election. While in parliament, Glynn served variously as Attorney General, Minister for External Affairs and Minister for Home and Territories.

|- style="text-align: center;" | width="30%" |Preceded by:
Billy Hughes | width="40%" style="text-align: center;" |Attorney General of Australia
1909–1910 | width="30%" |Succeeded by:
Billy Hughes