Cornelis Westerbeek (Sassenheim, April 13, 1844 – The Hague, October 22, 1903) was a Dutch painter and draftsman whose work is considered part of the Hague School. Within this influential movement, he developed a distinctive, recognizable approach to landscape, characterized by tonality, atmosphere, and a subdued color palette.

Like many Hague School artists, Westerbeek focused on the Dutch landscape: dunes, meadows, polders, and tranquil waterways. His paintings exude a restrained poetry. Instead of drama, he opted for nuance—soft transitions between sky and land, subtle effects of light, and an almost meditative tranquility. The weather, the seasons, and the diffuse Dutch light play a key role in his compositions.

As a draftsman, Westerbeek also demonstrated his mastery. With precise lines, he was able to suggest structure and depth, often exploring the same themes as in his paintings. His drawings are a valuable addition to his painted oeuvre and demonstrate how carefully he observed his subjects.

Westerbeek may not have occupied a loud, avant-garde position within the Hague School, but his work contributes to the movement's core: capturing mood over detail, atmosphere over anecdote. His oeuvre thus reflects a period in which the everyday landscape was elevated to a vehicle for emotion and identity.