Lawrence Gerard Nassar (born August 16, 1963) is an American former family medicine physician and serial child molester. From 1996 to 2014, he was the team doctor of the United States women's national gymnastics team, where he used his position to exploit and sexually assault hundreds of young athletes as part of the largest sexual abuse scandal in sports history.

In 2016, Nassar was arrested and charged with sexually assaulting at least 265 young women and girls under the guise of medical treatment. His victims included numerous Olympic and United States women's national gymnastics team gymnasts.

Nassar was sentenced to 60 years in federal prison on December 7, 2017, after pleading guilty to possession of child pornography and tampering with evidence on July 11, 2017. On January 24, 2018, Nassar was sentenced to an additional 40 to 175 years in Michigan State Prison, after pleading guilty in Ingham County to seven counts of sexual assault. On February 5, 2018, he was sentenced to an additional 40 to 125 years in Michigan State Prison after pleading guilty to an additional three counts of sexual assault in Eaton County.

The judge in charge of the federal case ordered his state and federal sentences to run consecutively, ensuring a de facto sentence of life imprisonment without parole. In the remote event that Nassar is still alive when he becomes eligible for release from federal custody, upon release he will immediately be transferred to a Michigan state prison to serve his two state sentences concurrently.

Nassar is a central figure of the 2020 film Athlete A, a documentary about the scandal.