"Hans Werner Henze, one of the most versatile and influential composers of our time has died," Schott said in a statement on its website.
He died in Dresden on Saturday, it said.
One of the most influential composers of the late 20th century, Henze wrote 10 symphonies and was especially known for his works for music theatre.
He was noted for his many operas and ballets, and for a commitment to political art, which informs much of his work.
Born on 1 July 1926 in Guetersloh, Germany, the son of a schoolteacher, Hans Werner Henze was initially educated at schools with a socialist outlook.
But, following the Nazi Party's ascent to power in 1933, he lived a dual life. While dutifully studying the official curriculum at school, he also played chamber music at a partly Jewish family house and there steeped himself in proscribed literature.
Henze's father was killed on the Eastern Front and Hans was conscripted into the army in 1944, ending the war in a British prisoner-of-war camp. His experiences left Henze with a lifelong hatred of fascism.
Celebrated German composer Hans Werner Henze has died at the age of 86, his publisher Schott Music has said.