Richard Courant (born January 8, 1888 at Lublinitz, today Poland, died January 27, 1972 at New York/USA) was a German and American mathematician.

During his youth, his parents had to move quite often, to Glatz, Breslau, and in 1905 to Berlin. He stayed at Breslau and entered the university there. As he found the courses not demanding enough he continued his studies at Zürich and Göttingen. He eventually became David Hilbert's assistant at Göttingen and obtained his doctorate there in 1910. He had to fight in World War I, but he was wounded and dismissed from the military service shortly after enlisting. He continued his research in Göttingen, with a two-year period as professor in Münster. There he founded there the Mathematical Institute, which he headed as director from 1928 until 1933.

Courant was Jewish and, earlier than many colleagues, he left Germany in 1933. After one year in Cambridge, he went to New York and became, in 1936, professor at the New York University. He was given the task to found an institute for graduate studies in mathematics, and very successful at that. The Courant Institute for Mathematical Sciences (as it was renamed in 1964) continues to be one of the most respected research centers in applied mathematics.

Apart from his outstanding organizational talent, Courant is well remembered for his mathematical achievements. He authored the very influential textbook Methods of mathematical physics which is still used after more than eighty years. He is the co-author with Herbert Robbins of a popularization titled What is Mathematics?, which is still in print. His name is also attached to the finite element method which, originally invented by engineers, he set on a solid mathematical basis and which applied to various problems. This method is nowadays the most important way to solve partial differential equations numerically.