Matthew Heineman (born June 6, 1983) is an American documentary filmmaker, director, and producer. His inspiration and fascination with American history led him to early success with the documentary film Cartel Land, which was nominated for an Academy Award for Best Documentary Feature Film, a BAFTA Award for Best Documentary, and won three Primetime Emmy Awards.

In 2009, Heineman founded his New York–based production company Our Time Projects, Inc., which would later release Our Time, his first documentary film about what it's like to be young in America, which he shot in the lower 48 states while traveling in an RV with three of his friends after graduating from college.

His 2021 film The First Wave received the Pare Lorentz Award from the International Documentary Association, was shortlisted for an Academy Award, and was nominated for seven Emmy Awards, winning Best Documentary, Best Cinematography, and Best Editing. The 2022 film Retrograde was nominated for the Directors Guild of America Award for Outstanding Directing at the Producers Guild of America Awards and won Outstanding Editing at the News and Documentary Emmy Awards.

Heineman was born June 6, 1983, to a Jewish family in Washington, D.C., the son of Cristine Russell and Ben Heineman, and grew up in Darien and New Canaan, Connecticut. He attended New Canaan Country School and Brunswick School in Greenwich. His mother is a science journalist and his father is a lawyer. His career as a filmmaker began after graduating from Dartmouth College in 2005. He studied history in college and initially wanted to be a teacher. Heineman was fascinated with American history, notably the American Civil War. He told C-SPAN in 2012, "I think it really taught me to be analytical, to think critically about events" and "try to learn from the past to affect the future."

He and his friends took a post-graduation trip across the U.S., and Heineman shot video along the way. He and his friends spent three months living out of an RV, interviewing kids "from all walks of life, trying to figure out what our generation is about." The resulting footage (which Heineman dubbed, "rough, guerilla filmmaking") became Our Time (2011), a feature-length documentary about American youth.

He began shopping around Our Time, which was self-produced via Our Time Projects, Inc., a production company Heineman founded in 2009. Heineman was hired at HBO and spent two years working on HBO's The Alzheimer's Project, a four-part documentary series. He was mentored by director Susan Froemke and producer John Hoffman.

Heineman worked with Froemke to direct and co-produce Escape Fire: The Fight to Rescue American Healthcare (2012). The film was later picked up and aired by CNN. The film received a New York Times Critics Pick. "This hard-hitting film leaves us finally more hopeful than despairing," wrote reviewer Jeannette Catsoulis.

A Private War stars Jamie Dornan, Tom Hollander, Stanley Tucci, and Oscar-nominee Rosamund Pike as legendary war reporter Marie Colvin. The film premiered at the 2018 Toronto International Film Festival before being released nationwide by Aviron Pictures. It was a New York Times Critics' Pick and Variety hailed the film as "Heineman's astonishing narrative debut," and "an incredibly sophisticated, psychologically immersive film." A Private War also earned two Golden Globe nominations for Best Actress and Best Original Song.