- 3 May 2005 – Lorin Maazel's opera 1984 had its world premiere at London's Royal Opera House.
- 5 May 1726 – Handel's opera Alessandro premiered at the King's Theatre in London with the celebrated Italian castrato singer Senesino in the title role.
- 8 May 1895 – Henry Clifford, an opera by the Spanish composer Isaac Albéniz, premiered at the Gran Teatre del Liceu in Barcelona.
- 10 May 1901 – The German tenor Max Lorenz, a famous interpreter of Wagnerian roles, was born in Düsseldorf.
- 18 May 1910 – The French opera singer and composer Pauline Viardot (pictured) died in Paris at the age of 89.
- 19 May 1894 – Verdi's last opera, Falstaff, received its first UK performance with Arturo Pessina in the title role.
- 22 May 1813 – The composer Richard Wagner was born in Leipzig. Twenty years later, he was to complete his first opera, Die Feen.
- 25 May 1869 – The Vienna State Opera House was officially inaugurated with a performance of Mozart's Don Giovanni.