John Arthur Heilemann (born January 23, 1966) is an American journalist and national affairs analyst for NBC News and MSNBC.

He was the host of a four-part documentary series for Discovery called Download: the True Story of the Internet, about the rise of the World Wide Web, which first aired in 2008.

He and Halperin co-hosted With All Due Respect (2014–2017), a political analysis show on Bloomberg Television and MSNBC.

Heilemann produces and co-stars in episodes of The Circus: Inside the Greatest Political Show on Earth, with Alex Wagner and Mark McKinnon, airing from 2016 to 2022.

Heilemann is also an occasional guest on The Tony Kornheiser Show and MSNBC's Deadline: White House, Morning Joe, and Real Time With Bill Maher.