William Jefferson Clinton (né Blythe III; born August 19, 1946) is an American politician who served as the 42nd president of the United States from 1993 to 2001. He previously served as governor of Arkansas from 1979 to 1981 and again from 1983 to 1992, and as attorney general of Arkansas from 1977 to 1979. A member of the Democratic Party, Clinton became known as a New Democrat, as many of his policies reflected a centrist "Third Way" political philosophy. He is the husband of Hillary Clinton, who was a senator from New York from 2001 to 2009, secretary of state from 2009 to 2013 and the Democratic nominee for president in the 2016 presidential election.

Clinton was born and raised in Arkansas and attended Georgetown University. He received a Rhodes Scholarship to study at University College, Oxford and later graduated from Yale Law School. He met Hillary Rodham at Yale; they married in 1975. After graduating from law school, Clinton returned to Arkansas and won election as state attorney general, followed by two non-consecutive terms as Arkansas governor. As governor, he overhauled the state's education system and served as chairman of the National Governors Association. Clinton was elected president in the 1992 presidential election, defeating incumbent Republican president George H. W. Bush and independent businessman Ross Perot. At 46 years old, he became the third-youngest president of the United States and the first president to be born in the Baby Boomer generation.

Clinton presided over the longest period of peacetime economic expansion in American history. He signed into law the North American Free Trade Agreement (NAFTA) and the Violent Crime Control and Law Enforcement Act, but failed to pass his plan for national health care reform. The Republican Party won unified control of Congress for the first time in 40 years in the 1994 elections, but Clinton was still comfortably re-elected in 1996, becoming the first Democrat since Franklin D. Roosevelt to win a second full term. Starting in the mid-1990s, he began an ideological evolution as he became much more conservative in his domestic policy, advocating for and signing the Personal Responsibility and Work Opportunity Act, the State Children's Health Insurance Program and financial deregulation measures. He appointed Ruth Bader Ginsburg and Stephen Breyer to the U.S. Supreme Court. During the last three years of Clinton's presidency, the Congressional Budget Office reported a budget surplus—the first such surplus since 1969. In foreign policy, Clinton ordered U.S. military intervention in the Bosnian and Kosovo wars, eventually signing the Dayton Peace agreement. He also called for the expansion of NATO in Eastern Europe and many former Warsaw Pact members joined NATO during his presidency. Clinton's foreign policy in the Middle East saw him sign the Iraq Liberation Act which gave aid to groups against Saddam Hussein. He also participated in the Oslo I Accord and Camp David Summit to advance the Israeli–Palestinian peace process, and assisted the Northern Ireland peace process.

Clinton's second term would be dominated by the Monica Lewinsky scandal which began in 1996, when he began a sexual relationship with 22-year-old Monica Lewinsky, an intern at the White House. In January 1998, news of the affair made tabloid headlines. The scandal escalated throughout the year, culminating on December 19 when Clinton was impeached by the House of Representatives, becoming the second U.S. president to be impeached after Andrew Johnson. The two impeachment articles that the House passed were centered around Clinton using the powers of the presidency to obstruct the investigation and that he lied under oath. In 1999, Clinton's impeachment trial began in the Senate. Clinton was acquitted on both charges as the Senate failed to cast 67 votes against him, the conviction threshold.

Clinton left office in 2001 with the joint-highest approval rating of any U.S. president in the modern era, alongside Franklin D. Roosevelt and Ronald Reagan. His presidency has been ranked among the upper tier in historical rankings of U.S. presidents. However, his personal conduct and allegations of sexual assault have made him the subject of substantial scrutiny. Since leaving office, he has been involved in public speaking and humanitarian work. He created the Clinton Foundation to address international causes such as the prevention of HIV/AIDS and global warming. In 2009, he was named the United Nations Special Envoy to Haiti. After the 2010 Haiti earthquake, Clinton and George W. Bush formed the Clinton Bush Haiti Fund. He has remained active in Democratic Party politics, campaigning for his wife's 2008 and 2016 presidential campaigns.