Loren Klein (sometimes L.J. Klein) is a professional poker player who has won four World Series of Poker bracelets. He began playing online in about 2007 and began live play in 2011 following Black Friday in 2011. He won World Series of Poker bracelets at the 2016, 2017 and 2018 and 2019 World Series of Poker. Klein was the third player to win bracelets in three consecutive years (following Allen Cunningham 2005–07 and Matt Matros 2010–12) since the poker boom.