Erminia Frezzolini (27 March 1818 – 5 November 1884) was an Italian operatic soprano. She excelled in the coloratura soprano repertoire, drawing particular acclaim in the bel canto operas of Gaetano Donizetti and Vincenzo Bellini. She was married to tenor Antonio Poggi from 1841-1846.
Born in Orvieto, Frezzolini initially studied singing with her father, the famous bass Giuseppe Frezzolini. She then studied in Milan with Domenico Ronconi and in Florence with Andrea Nencini and N. Tachinardi. At the advice of Maria Malibran she pursued further studies with Manuel Patricio Rodríguez García.
In 1837 Frezzolini made her professional opera debut in the title role of Bellini's Beatrice di Tenda at the Teatro della Pergola in Florence. She quickly arose in major opera houses throughout Italy, often in the operas of Bellini and Donizetti. In 1838 she was heard at the opera houses in Siena and Ferrara. In 1839 she portrayed the title role in the house premiere of Saverio Mercadante's Elena da Feltre at the Teatro Comunale di Bologna.
She sang several more roles in Bologna in 1838-1839, including the title roles in Anna Bolena, Beatrice di Tenda, and Lucia di Lammermoor. She made her debut at La Scala in 1839 as Bianca in Mercadante's Le due illustri rivali. She also made her debuts that year at the opera houses in Pisa, Reggio Emilia, and Perugia.