Erin Morley (born October 11, 1980) is an American operatic soprano.

Morley was born in Salt Lake City, Utah to David Palmer, a former singer in the Tabernacle Choir, and Elizabeth Palmer, a current concertmaster of the Salt Lake Symphony. In grade school she studied piano with Solveig Lunde Madsen (a star pupil of Olga Samaroff), and then with Douglas Humpherys at the Eastman School of Music. Her first professional singing engagements were with the Utah Symphony with Joseph Silverstein and with the Tabernacle Choir on their worldwide broadcast Music & the Spoken Word under the baton of Craig Jessop.

Morley obtained her undergraduate voice degree from Eastman School of Music, her Master of Music voice degree from the Juilliard School, and her Artist Diploma from the Juilliard Opera Center. Morley also trained at the Lindemann Young Artist Development Program, the Opera Theatre of Saint Louis, the Ravinia Festival Steans Institute, and the Wolf Trap Opera Company.

Morley has performed at Carnegie Hall, The Metropolitan Opera, Opéra National de Paris, Royal Opera House, Bavarian State Opera, Vienna State Opera, Teatro alla Scala, Glyndebourne Festival Opera, Gran Teatre del Liceu, LA Opera, and Santa Fe Opera. Morley's debut at the Met was as First Madrigal in Manon Lescaut in 2008. She made her Teatro alla Scala debut in 2022 as Zerbinetta in Ariadne auf Naxos, and her Royal Opera House debut in 2023 as Gilda in Rigoletto. She also debuted at the BBC Proms that same year. She is recognized worldwide for her signature roles of Sophie in Der Rosenkavalier, Gilda in Rigoletto, Zerbinetta in Ariadne auf Naxos, and Olympia in Les Contes d'Hoffmann.

Morley's breakthrough career moment came when she stepped in at the last minute to sing Sophie in Der Rosenkavalier at the Metropolitan Opera during the 2013–2014 season, which was hailed as "a major success". She has since sung more than 100 performances at the Met and has been featured in seven "Live in HD" broadcasts. She has been described by The New York Times as a "limpid, fluid soprano", "silken clarity", and "needlepoint precision". In September 2018 she made her debut, while being 34 weeks pregnant, in Debussy's Le Martyre de saint Sébastien with the Deutsches Symphonie-Orchester Berlin.

Career highlights include Morgana in Handel's Alcina and Zerbinetta in Ariadne auf Naxos both at Teatro alla Scala, the title role in Matthew Aucoin's Eurydice and Sophie in Der Rosenkavalier both with The Metropolitan Opera, and Gilda in RigolettoRigoletto with Wiener Staatsoper and Bayerische Staatsoper. She performed as Queen Marguerite in Les Huguenots at Bard College (2009), Cunegonde in Candide at Los Angeles Opera (2018) and in concert at Carnegie Hall (2018) and with the Philadelphia Orchestra (2019). Her Zerbinetta at Teatro La Fenice (2024) for her debut at the theater was also their first time staging Ariadne auf Naxos.

On operatic and concert stages, Morley has collaborated with celebrated conductors worldwide, including Riccardo Muti, Christian Thielemann, Riccardo Chailly, Gustavo Dudamel, Yannick Nézet-Séguin, Andris Nelsons, Seiji Ozawa, James Levine, and Bernard Haitink. Highlights of her concert performances include Orff's Carmina Burana with the Orchestre de Paris and with the Boston Symphony Orchestra at Tanglewood, Poulenc's Gloria with Houston Symphony Orchestra, Brahms' Ein deutsches Requiem with Orchestra of St. Luke's at Carnegie Hall, Beethoven's Missa Solemnis with the Chicago Symphony Orchestra, and Mozart's Mass in C Minor with the Mostly Mozart Festival at Lincoln Center, among many others.

When the COVID-19 pandemic struck, Morley was set to sing the part of Sophie in Werther for the Met's music director, Yannick Nézet-Séguin.