Mark Twang is a 1976 album by American bluegrass singer-songwriter and instrumentalist John Hartford.

Much of his songs for the album were inspired by Hartford's experiences working on a riverboat, notably "The Julia Belle Swain" and "Let Him Go on Mama."

During the four-year break since the end of his contract with Warner Bros. Records and the release of Morning Bugle, Hartford earned his riverboat pilot's license, played live or sat in on others' records, and signed with the independent label Flying Fish.

[1] Writing for Allmusic, critic Ronnie D. Lankford, Jr. wrote of the album "The songs, as usual, run from sentimental to strange, from the romantic to the weird... Mark Twang may not be the first stopping place for the new Hartford fan, but for those already familiar with his unique talent, it's a must have.

He's slightly the better for it, on the whole—but I wouldn't say his living sounds so secure that he should turn down a gig on the Proud Mary.