It depends on what the meaning of the word 'is' is.
Analysis
The statement is a direct quote from Bill Clinton's August 17, 1998, grand jury testimony regarding his relationship with Monica Lewinsky. He used this phrasing while being questioned about the definition of 'is' in the context of his previous deposition. The quote is widely documented and verified in official transcripts.
Background
The testimony was part of the investigation into the Clinton-Lewinsky scandal, where Clinton was accused of perjury and obstruction of justice. His parsing of the word 'is' became a notable example of legalistic language in political discourse.
Verdict summary
Clinton did say this exact phrase during his 1998 grand jury testimony.
Sources consulted
— Grand Jury Testimony of William Jefferson Clinton (1998), U.S. House of Representatives
— The Starr Report (1998), Independent Counsel Investigation
— Transcript: Clinton's Grand Jury Testimony (CNN, 1998)