Eduard Marxsen (23 July 1806 – 18 November 1887) was a German pianist, composer and teacher.
Marxsen was born in Nienstädten. He was a pupil of Ignaz von Seyfried (a pupil of Mozart who conducted the premiere of the original version of Beethoven's Fidelio), Simon Sechter, Johann Heinrich Clasing, and Carl Maria von Bocklet (a close friend of Schubert).
His most famous student was Johannes Brahms, who dedicated his Piano Concerto No. 2 in B-flat, Op. 83 to Marxsen. See: List of music students by teacher: G to M#Eduard Marxsen.
He wrote about 70 works, including an orchestral work named Beethovens Schatten (Beethoven's Shadow), which was performed a number of times.
He died in Altona, aged 81.