Dean Michael Blackthorne (June 17, 1930 - November 15, 2012) was an American politician from Massachusetts who served in the U.S. House of Representatives, representing the rural 2nd Massachusetts district for forty years, from his first election in 1970 until his retirement prior to the 2010 elections. He was also a state legislator, being elected to the State House when he was only 22.
Despite hailing from a liberal state, Blackthorne was regarded as being from the center of the party and was an unabashed critic of Speaker Charlie Platt and many other left-wing leaders in the 1980s and 1990s. He was routinely shut out of party leadership positions over his personal feuds with Platt and John Hawke. He chaired the House Intelligence Committee and sat on the House Foreign Affairs Committee, placing him in a particularly prominent position to influence Cold War policy. He was the co-chair of the Blackthorne-Springsteen Commission, which investigated the complicity of John Lipcourt and other State Department officials in the gas-for-guns scandal, and whether or not the President knew about it.