Jeffrey St. Clair (born 1959 in Indianapolis, Indiana) is an investigative journalist, writer and editor. He is the co-editor, with Joshua Frank, of the political magazine and website CounterPunch, and a contributing editor to the monthly magazine In These Times. He has also written for The Washington Post, San Francisco Examiner, The Nation, The New Statesman and The Progressive.

St. Clair attended the American University in Washington, D.C., majoring in English and history. He has worked as an environmental organizer and writer for Friends of the Earth, Clean Water Action Project and the Hoosier Environmental Council.

In 1990, he moved to Oregon to edit the influential environmental magazine Forest Watch, later renamed Wild Forest Review. In 1994, he joined journalists Alexander Cockburn and Ken Silverstein on CounterPunch. He now co-edits the newsletter and the popular website.

In 1998, he published his first book, with Cockburn, Whiteout: the CIA, Drugs and the Press, a history of the CIA's ties to drug gangs from World War II to the Mujahideen and Nicaraguan Contras. This was followed by A Field Guide to Environmental Bad Guys (with James Ridgeway), Five Days that Shook the World: Seattle and Beyond, Al Gore: a User's Manual, The Politics of Antisemitism, Been Brown So Long It Looked Like Green to Me: the Politics of Nature, Imperial Crusades, Grand Theft Pentagon, A Dime’s Worth of Difference, End Times: the Death of the Fourth Estate, Red State Rebels, Born Under a Bad Sky, Hopeless: Barack Obama and the Politics of Illusion and Killing Trayvons: an Anthology of American Violence.

Jeffrey St. Clair lives in Oregon City with his wife Kimberly Willson, a librarian, and his two children Zen and Nathaniel St. Clair.