Johann Ernst Bach (born 1683; died 1739) (also known as Johannes Ernestus Bach ) was a German organist in the Bach family, and son of Johann Christoph Bach senior – twin brother of Johann Sebastian Bach's father, Johann Ambrosius Bach.
Like his cousin Johann Sebastian, Johann Ernst attended Ohrdruf Lyzeum.
From April 1701, he lived in Hamburg for half a year, to study the organ.Johann Ernst visited Johann Sebastian when he moved from Arnstadt to Lübeck to hear the famous organist in Marienkirche, Buxtehude, and in 1707, he was named as Johann Sebastian's successor as organist in Arnstadt.