Lawrence Gerard Nassar (born August 16, 1963) is an American convicted sex offender, serial child molester, and former sports medicine physician. For 18 years, he was the team doctor of the United States women's national gymnastics team, where he used his position of power to exploit and sexually assaulthundreds of young athletes.

In 2016, Nassar was 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 teamgymnasts.

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.

On the orders of the judge in charge of the federal case, his state prison sentences are to run consecutively with his federal sentence, ensuring a de facto sentence of life imprisonment without parole.

Nassar will be transferred to a Michigan state prison when he is released from federal custody; his two state sentences will be served concurrently.

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