John Carreyrou (/ˌkæriˈruː/) is a French-American journalist and writer who worked for The Wall Street Journal for 20 years between 1999 and 2019 and has been based in Brussels, Paris, and New York City. He won the Pulitzer Prize twice and is well known for having exposed the fraudulent practices of the multibillion-dollar blood-testing company Theranos in a series of articles published in The Wall Street Journal.