Jenůfa About this sound is an opera in three acts by Leoš Janáček to a Czech libretto by the composer, based on the play Její pastorkyňa by Gabriela Preissová. It was first performed at the Brno Theater, Brno, 21 January 1904. It was written between 1896 and 1902, and counts among the first operas written in prose.

The first of Janáček's operas in which his distinctive voice can clearly be heard, it is a grim story of infanticide and redemption. Like the playwright's original work, it is known for its unsentimental realism. While today it is heard in the composer's original version, Jenůfa's early popularity was fostered by a revision by Karel Kovařovic of what was considered its eccentric style and orchestration. Thus altered, it was well-received, first in Prague, and particularly after its Vienna première also worldwide. More than 70 years were to pass before audiences heard it as Janáček had intended it to be performed.

Janáček wrote an overture to the opera, but decided not to use it. It was partly based on a song called Žárlivec (The jealous man). It is now performed as a concert piece under the title Žárlivost (Jealousy), JW 6/10.

The composer dedicated the work to the memory of his dead daughter Olga, as he also did with his choral composition called the Elegy on the Death of Daughter Olga.