Robert Frank Grill (November 30, 1943 – July 11, 2011)[1] was an American musician and songwriter, best known as lead singer and bassist of the rock and roll group The Grass Roots.

Soon after graduation, he began working at American Recording Studios with musician friends Cory Wells and John Kay (who later formed Three Dog Night and Steppenwolf, respectively).

Grill was asked to join The Grass Roots, which grew out of a project originating from Dunhill Records owned by Lou Adler.

Sloan and Steve Barri (The Mamas & the Papas, Tommy Roe, Four Tops and Dusty Springfield) were asked by Dunhill to write songs that would capitalize on the growing interest in the folk-rock movement.

After the first group they chose departed, a Los Angeles band composed of Creed Bratton, Rick Coonce, Warren Entner, and Kenny Fukomoto was recruited to become The Grass Roots.

The Grass Roots played at Newport Pop Festival 1969 at Devonshire Downs, which was a racetrack at the time but now is part of the North Campus for California State University at Northridge.