David Helvarg is an American journalist and environmental activist. He is the founder and president of the marine conservation lobbying organization Blue Frontier Campaign. He is also a participant in the Seaweed rebellion, an informal marine environmentalist activist movement. He is an author; his writing is often related to marine environmental activism, such as his second book, Blue Frontier. His first book, The War against the Greens, argues that violent organized resistance is being orchestrated against the environmental movement.

Helvarg was born April 10, 1951, in New York City, the son of refugees; his mother left Nazi Germany and his father escaped civil war in Ukraine. He grew up on Long Island, where he became a civil rights and anti-war activist. He attended Boston University and earned a bachelor's degree in history from Goddard College in Vermont, in 1974.

Helvarg won his first national award in 1988 when he won an Emmy for community service in recognition of his work on AIDS Lifeline, a networked television AIDS awareness campaign. His subsequent awards include two National Association for Interpretation awards for Interpretive Communications (in 1989 and 1991), the Nike Earthwrite Award (1997), a National Health Information Award (1999) and a CINE Golden Eagle Award (1999). In 2005, Coastal Living magazine gave him their Leadership Award. In 2007 he won the Herman Melville Award.