Cao Văn Lầu (1892–1976), also known as Sáu Lầu (Lầu the Sixth in Vietnamese), was a Vietnamese musician. He was the original composer of the song vọng cổ which started a new genre of cải lương music in the 1920s.

He was born on 22 December 1892 in Long An province, French Cochinchina. At the age of 4, he moved to Bạc Liêu and spent all his life there. In Bạc Liêu, he studied Hán tự with a monk and then attended a French primary school. In 1907, Lầu stopped schooling because of his poverty. In 1908, he began learning music from local musician Lê Tài Khí and began his music career four year later. In 1913, he married a woman named Trần Thị Tấn.

Because Tấn was not pregnant after three year of marriage, Lầu was forced to send his wife back to her family due to local custom. This separation was inspired Cao Văn Lầu in comprising his best known love-song Dạ cổ hoài lang (Night Drum Beats Cause Longing for Absent Husband), a song that have a great influence in cải lương music. He died on August 13, 1976 in Bạc Liêu.