FiveThirtyEight, which takes its name from the number of electors in the United States electoral college, was founded on March 7, 2008, as a polling aggregation website with a blog created by analyst Nate Silver.

In August 2010, the blog became a licensed feature of The New York Times online.

In July 2013, ESPN announced ownership of the FiveThirtyEight brand and site, and Nate Silver was appointed editor-in-chief. The ESPN-owned FiveThirtyEight began publication on March 17, 2014.