Hermanus Koekkoek de Jonge Amsterdam, December 8, 1836 - London, May 1909), was a Dutch painter, best known for his seascapes. Romantic-realistic & later The Hague School

Life and work: He also worked under the pseudonyms Jan van Couver and Louis van Straaten. Hermanus Koekkoek de Jonge was part of the famous Koekkoek family of painters. He was the grandson of Johannes Hermanus Koekkoek, nephew of the famous landscape painter Barend Cornelis Koekkoek and son of his brother Hermanus Koekkoek the Elder (1815-1887). His son Stephen Robert Koekkoek (1887-1934) also chose to paint. Hermanus Koekkoek de Jonge, like his brothers Willem, Johannes Hermanus Barend and Barend Hendrik, was trained by his father, who had just settled in Amsterdam.

In the 1860s he traveled regularly to London, only to settle there permanently in 1869. He ran an art trade there with great success and, in addition to his own work, also sold many paintings by his family members. The great popularity of his uncle Barend Cornelis in England was largely due to him.

As a painter he mainly focused on sea, river and beach scenes, in the romantic-realistic style that also characterized the work of most of his family members. He had a preference for scenes in which ships were busy keeping course on the turbulent waves. His later work is less romantic and shows emphatic influences from the Hague School. In his London period he often worked under the pseudonyms Jan van Couver and Louis van Straaten. He regularly collaborated with the painter Lion Schulman (1851-1943).