Heinrich Scheidemann (ca. 1595 – 1663) was a German organist and composer. He was the best-known composer for the organ in north Germany in the early to mid-17th century, and was an important forerunner of Dieterich Buxtehude and J.S. Bach.
He was born in Wöhrden in Holstein. His father was an organist in both Wöhrden and Hamburg, and he probably received some early instruction from him. He studied with Sweelinck in Amsterdam from 1611 to 1614, and evidently was one of his favorite pupils, since Sweelinck dedicated a canon to him, prior to Scheidemann's return to Germany. By 1629, and possibly earlier, Scheidemann was in Hamburg as organist at the Catharinenkirche, a position which he held for more than thirty years, until his death in Hamburg in early 1663 during an outbreak of the plague.
Scheidemann was renowned as an organist and composer, as evidenced by the wide distribution of his works; more organ music by Scheidemann survives than by any other composer of the time. His lasting contribution to the organ literature, and to Baroque music in general, was in his Lutheran chorale settings. Among his students were Johann Adam Reincken, his successor at the St. Catharine Church in Hamburg, and Dieterich Buxtehude.