Mark Randall Volman (April 19, 1947 – September 5, 2025) was an American vocalist, guitarist and songwriter who was best known as a founding member of the 1960s rock band the Turtles. With his bandmate and friend Howard Kaylan, he was a member of the 1970s rock duo Flo & Eddie, in which he used the pseudonym Flo (short for The Phlorescent Leech). Volman later joined Frank Zappa's band The Mothers of Invention.

Volman was born in Los Angeles, California, on April 19, 1947 to a Jewish father, Joe Yarnatinski, who changed his name to Volman, and a Catholic mother, Bea (nee Campillo). He grew up in Westchester, a suburb of Los Angeles, where he performed in his mid-teens with Kaylan in a proto-Turtles band called The Crossfires. He graduated from Westchester High School in 1965.

Volman and Howard Kaylan were founding members of the Turtles, a popular band of the late 1960s. In 1965, shortly after leaving school, they were touring with Herman's Hermits and playing to audiences of 50,000. Their cover of Bob Dylan's "It Ain't Me Babe" gave them a Top Ten hit. They had another US Top 20 hit in 1966 with "You Baby". "Happy Together" replaced the Beatles at Number One in early 1967 and they sang it on the Ed Sullivan Show. Volman and Kaylan had sung together in their school choir, and further hits, characterised by their "pristine Beach Boys-style harmony vocals", included "She'd Rather Be With Me" and "Elenore".

In December 1968, NME magazine reported that Volman had insured his distinctive frizzy hair for US$100,000 against fire, theft or loss due to illness. The band folded in 1970. Volman and Kaylan planned to continue working together, but discovered that the terms of their contract forbade them to use not only the name 'The Turtles' but also their own names. They reinvented themselves as the Phlorescent Leech & Eddie, which was shortened to Flo and Eddie when they were recruited by Frank Zappa to join the Mothers of Invention. They worked together as Flo & Eddie in music, providing backing vocals for T.Rex and Bruce Springsteen and touring with Alice Cooper; in film (they provided music and voices for animated films like Down and Dirty Duck); and in radio broadcasting. Alice Cooper was quoted as saying "They had such pure voices. Everybody wanted to work with Mark and Howard." They made several albums of sardonic songs under the Flo & Eddie name. In 1971 Volman appeared in and on the soundtrack to Zappa's humorous pseudo-documentary film, 200 Motels. In the mid-1980's they regained possession of their naming rights after a "long legal battle".

In 2015, Kaylan and Volman celebrated their 50th year, touring and performing more than 60 concerts a year, billed as "The Turtles ... Featuring Flo & Eddie" with their Happy Together Tour, a classic revue-format show featuring some popular bands of the mid-to-late 1960s musical era. During this tour in 2015, Volman was diagnosed with throat cancer, but was declared cancer-free in 2016. Kaylan retired in 2018 because of ill health.

According to The Hollywood Reporter, Volman and Kaylan had been "leading the charge against the uncompensated use of their music, and using state-based misappropriation, conversation [sic] and unfair competition claims because sound recordings only began falling under federal copyright protection in 1972."

In 2023, Volman co-wrote his biography with John Cody and several other former bandmates and colleagues, titled Happy Forever: My Musical Adventures With The Turtles, Frank Zappa, T. Rex, Flo & Eddie, And More.

In 1992, at age 45, Volman started his bachelor's degree at Loyola Marymount University. He was an active undergraduate member of the choir and a Founding Father of the California Chi chapter of Sigma Phi Epsilon fraternity. Volman graduated with a B.A. degree in 1997 magna cum laude and was the class valedictorian speaker. During the speech he led the graduates in a chorus of "Happy Together". CBS Evening News covered Volman's graduation and interviewed his parents, who were perplexed at their son's academic accomplishments.^{[failed verification]}