- 15 October 1932 – San Francisco Opera inaugurated the new War Memorial Opera House with a performance of Tosca. Claudia Muzio (pictured) sang the title role.
- 18 October 1810 – The celebrated Italian tenor Mario (Cavalier Giovanni Matteo de Candia, Marquis of Candia) was born in Cagliari.
- 19 October 1701 – La púrpura de la rosa, the first known opera to be composed and performed in the Americas, premiered at the Viceroy's Palace in Lima, Peru.
- 20 October 1973 – The Sydney Opera House was formally opened by Queen Elizabeth II.
- 22 October 1987 – John Adams' opera Nixon in China had its world premiere at the Houston Grand Opera in a production by Peter Sellars with choreography by Mark Morris.
- 24 October 1948 – Franz Lehár, the composer of The Merry Widow, died in Bad Ischl, Austria.
- 27 October 1922 – Rita Fornia, the soprano who created the role of the Abbess in Puccini's Suor Angelica, died in Paris at the age of 44.
- 29 October 1787 – Mozart's opera Don Giovanni had its world premiere at the Estates Theatre in Prague, with Luigi Bassi in the title role.