L'ange de Nisida (The Angel of Nisida) is an opera semiseria in four acts by Italian composer Gaetano Donizetti, from a libretto by Alphonse Royer and Gustave Vaëz.

Parts of the libretto are considered analogous with the libretto for Giovanni Pacini's Adelaide e Comingio, and the final scene is based on the François-Thomas-Marie de Baculard d'Arnaud play Les Amants malheureux, ou le comte de Comminges. Donizetti worked on the opera in late 1839—its final page is dated 27 December 1839. Because the subject matter involved the mistress of a Neapolitan king, and may thus have caused difficulties with the Italian censors, Donizetti decided that the opera should be presented in France. The theater company Donizetti contracted went bankrupt; L'ange was never performed and was reworked as La favorite in September 1840.

L'ange de Nisida incorporated many of the manuscript pages from Adelaide, an unfinished score that Italian composer Gaetano Donizetti was probably working on in 1834, from a libretto of unknown origin. This libretto contained elements from the 1790 Parisian play Les Amants malheureux, ou le comte de Comminges by François-Thomas-Marie de Baculard d'Arnaud. In his book Donizetti and his Operas, musicologist William Ashbrook states that the Adelaide libretto has similarities to that of the Giovanni Pacini opera Adelaide e Comingio, whose libretto was written by Gaetano Rossi. Donizetti is believed to have taken the manuscript for Adelaide to Paris in 1838. Because the subject matter of L'ange involved the mistress of a Neapolitan king, and may thus have caused difficulties with the Italian censors, Donizetti decided that the opera should be presented in France. Additionally, in September 1839, the French press had announced La Fiancée du Tyrol, a translation of Donizetti's 1833 opera Il furioso all'isola di San Domingo. In October 1839, he wrote to a friend in Naples: "La Fiancée du Tyrol will be Il furioso amplified, L'ange de Nisida will be new." Donizetti began work on L'ange shortly thereafter; La Fiancée du Tyrol never materialized.