Michael Ralph Thomas Gunn (1840 – 24 October 1901) was an Irish businessman and theater manager who built and ran the Gaiety Theatre, Dublin.

They spent three years in Clare Street and then in 1850 opened a business at 13 Westland Row[a] selling pianofortes and harmoniums.

[3] In 1861 their father died in a horse-drawn omnibus accident when the driver lost control and the vehicle was backed into a canal lock.

[1] In November 1872 Michael Gunn stood as a candidate for the Royal Exchange ward of the Dublin Municipal Council.

[5] He held his seat on the Municipal Council until November 1878 when he had to retire from this position due to the demands of his business enterprises.

[2] On 21 April 1871 John and Michael Gunn obtained a 21-year license to establish "a well-regulated theatre and therein at all times publicly to act, represent or perform any interlude, tragedy, comedy, prelude, opera, burletta, play, farce or pantomime".

The Lord Mayor of Dublin laid the foundation stone in a ceremony on 1 July 1871, although by that time the work was already quite advanced.

[10] While other Dublin theaters had resident performers and technical staff, the Gaiety provided a stage for touring companies almost all year apart from Christmas, when it put on a pantomime produced in-house.

[7] In March 1874 the Gunn brothers acquired the Theatre Royal, Dublin from John Harris,[11] who had run it for nearly 25 years.

[12] Michael Gunn opened the programme at the Theatre Royal, just a week after taking over, on April 5, 1874 with The Lancashire Lass.

[16] In June 1875 the Madame Dolaro Company, managed by Richard D'Oyly Carte, went on tour in England and Ireland performing La Périchole, La fille de Madame Angot, and Trial by Jury by Gilbert and Sullivan.

[19] In June 1879 Carte left to arrange Gilbert and Sullivan productions in the United States after appointing Gunn to manage his opera business in England during his absence.

[citation needed] At the start of 1882 Carte was bound for New York, while Gunn was supervising the Gilbert and Sullivan touring companies and managing the Savoy Theatre.

[23] The prospectus of the Savoy Hotel, issued a few months before it opened in August 1889, listed Gunn among the directors.

[23] Matcham redecorated the auditorium in baroque style and built an extension to the west that held the parterre and dress-circle bars.

[26] Gunn was attracted to a member of Carte's 1875 company, Barbara Johnstone, who used the stage name Bessie Sudlow.

[14] Carte was Michael Gunn's best man when he married Johnstone on 26 October 1876 at the St Marylebone Parish Church, London.