Guy Lorin Reschenthaler (/ˈrɛʃənˌθɑːlər/ RESH-ən-THAHL-ər; born April 17, 1983) is an American politician, attorney, judge, and U.S. Navy veteran. A Republican, he is serving as the U.S. representative for Pennsylvania's 14th congressional district since 2019 and was previously a member of the Pennsylvania State Senate, representing the 37th district. He served as a district judge, and in the U.S. Navy Judge Advocate General's Corps (JAG) during the Iraq War. He is serving as the Republican Chief Deputy Whip in the 119th Congress.

Reschenthaler was born in Pittsburgh on April 17, 1983. He was raised in Pittsburgh's South Hills and graduated from Thomas Jefferson High School in 2001. He graduated from Penn State Erie, The Behrend College in 2004 with a Bachelor of Arts degree in political science. Upon graduation, Reschenthaler attended Duquesne University School of Law in Pittsburgh, earning a Juris Doctor in 2007. At Duquesne, Reschenthaler founded the Military Law Society chapter and interned at the U.S. District Attorney's Office for the Western District of Pennsylvania in Pittsburgh.

After law school, Reschenthaler was commissioned in the United States Navy Judge Advocate General's Corps (JAG). In the U.S. Navy, Reschenthaler deployed to Baghdad, Iraq, in 2009. In 2010, he was one of three attorneys who defended a Navy SEAL accused of covering up an assault on terrorist Ahmad Hashim Abd al-Isawi while al-Isawi was in custody. The Navy SEAL represented by Reschenthaler and the other SEALs charged were acquitted of all charges. Reschenthaler was awarded the Michael Taylor Shelby Award for Professionalism, Ethics and Dedication in the practice of law. He left military service in 2012.

After leaving the Navy, Reschenthaler returned to Pittsburgh to practice law in spring 2012 before being elected magisterial district judge in Pittsburgh's South Hills in 2013. In Pennsylvania, magisterial judges typically handle traffic tickets. He was elected district judge in May 2013. As a magistrate, Reschenthaler said that he would seek to reduce truancy.

In 2013, Reschenthaler briefly co-hosted a radio program with Carl Higbie. Reschenthaler had heated debates with Higbie on the show, with CNN reporting that, "In one episode in March 2013, after Higbie repeatedly argued that 'the black race' was 'lazier than the white race,' Reschenthaler became audibly upset at his co-host. The congressional candidate said that he was 'turning red' and 'feeling uncomfortable' listening to Higbie's rant, which he called 'insane' and 'so off-base.'"

Reschenthaler also wrote the foreword to a 2012 self-published book by Higbie. In April 2018, Reschenthaler denounced the book and disavowed the foreword he had written. He said he had only read parts of the book.

Reschenthaler was of counsel at Pittsburgh law firm Brennan, Robins & Daley and serves as a member of Penn State Behrend's Political Science Advisory Board.

After State Senator Matt Smith resigned, Reschenthaler won the Republican nomination for a special election in the 37th state Senate district in July 2015. He defeated the Democratic nominee, Heather Arnet, in the general election to serve the remainder of Smith's term, ending in 2016. He was sworn in on November 24, 2015.