Walter Thomas Hampson (born June 28, 1955) is an American lyric baritone, a classical singer who has appeared world-wide in major opera houses and concert halls and made over 170 musical recordings.

Hampson's operatic repertoire spans a range of more than 80 roles, including the title roles in Mozart's Don Giovanni, Rossini's Guillaume Tell and Il barbiere di Siviglia, Thomas' Hamlet, and Tchaikovsky's Eugene Onegin. The center of his Verdi repertoire remains Posa in Don Carlo, Germont in La traviata, the title roles in Macbeth and Simon Boccanegra, and more recently also Amfortas in Wagner's Parsifal and Scarpia in Puccini's Tosca.

As a recitalist Hampson has won worldwide recognition for his thoughtfully researched and creatively constructed programs that explore the rich repertoire of song in a wide range of styles, languages, and periods. He is one of the most important interpreters of German Romantic song – especially known for his interpretations of the music of Gustav Mahler – and, with his "Song of America" project collaboration with the Library of Congress, has become known as the "ambassador" of American song.

Hampson's diverse and expansive discography has earned him an Edison Award for Lifetime Achievement, four Edison Awards, four Echo prizes, numerous VEB Deutsche Schallplatten, Gramophone Awards, and Grand Prix du Disque, as well as six Grammy Award nominations, and one Grammy Award. Vienna Acoustics, an Austrian music company, named one of their speakers "The Hampson Edition."

Dame Elisabeth Schwarzkopf once said of her student, "[Thomas Hampson is] the best singer in Europe right now."

Born in Elkhart, Indiana, Hampson has two older sisters, with whom he sang in church as a child. He grew up in Spokane, Washington, where he enrolled at Eastern Washington State College (now Eastern Washington University) in Cheney, majoring in political science/government. Concurrently, Hampson earned a BFA in Voice Performance at Fort Wright College under the tutelage of Sister Marietta Coyle. During the summers of 1978 and 1979, he studied under Gwendolyn Koldowsky and Martial Singher at the Music Academy of the West, where he won the Lotte Lehmann Award. He then continued his studies at the University of Southern California Thornton School of Music, where he worked with vocal coach Jack Metz and the baritone Horst Günter, a lifelong mentor. In 1980, as a consequence of winning the San Francisco Opera audition, he competed in the Merola Opera Program, in which he met Elisabeth Schwarzkopf. In 1981, he was one of the winners in the Metropolitan Opera National Council Auditions national finals.

An audition tour in Europe in the early 1980s brought him a contract with the Deutsche Oper am Rhein in Düsseldorf, as well as the opportunity to study with Dame Elisabeth Schwarzkopf, whom he had met at the Merola program. In his three years as a member of the Düsseldorf ensemble (1981–84), he honed his stage experience with a number of smaller roles, but also had bigger assignments, both in Düsseldorf and elsewhere. He sang the title role in Henze's Der Prinz von Homburg in Darmstadt, and Guglielmo, in a Jonathan Miller production of Mozart's Così fan tutte at the Opera Theatre of Saint Louis, which brought him significant attention in the United States.

In 1984, he began an engagement at the Opernhaus Zürich as a principal lyric baritone, among others participating in the legendary Harnoncourt-Ponnelle Mozart cycle, including all of the Da Ponte operas and the title role of the famed 1987 production of Don Giovanni. Engagements during this time also included those with companies in Hamburg, Cologne, and Vienna, and his 1984 London recital debut at Wigmore Hall.