Pekka Kostiainen (born on 16 March 1944) is a composer and choral conductor. He graduated from the Sibelius Academy as a cantor and continued studies in composition with Einar Englund, Joonas Kokkonen, Einojuhani Rautavaara and others. Before becoming a freelance composer and conductor, Kostiainen was a lecturer of music at the University of Jyväskylä.
Choral music constitutes the majority of Kostiainen works, however, there are also orchestral works in his oeuvre. The most frequently-performed choral pieces include The Sons of Jacob playing with Biblical names (there is also a mixed-choir version called The Big Sons of Jacob). While humorous works for children’s choir occupy a prominent position in Kostiainen’s output, he has also composed music for the church. Fennica Gehrman has published his choral works and the Concertino for Piano and Orchestra.