Jill Stein, a physician from Massachusetts, announced her entry into the 2016 United States presidential election on June 22, 2015.

[2] On August 1, 2016, Stein announced that she had selected international human rights activist Ajamu Baraka as her running mate.

[10] In a June 2015 interview on The Alan Colmes Show, Stein said that she would announce her intention to run for President "certainly before the summer is up, probably a lot sooner than that".

[11] In December 2015, Stein took part in the 2015 United Nations Climate Change Conference (COP 21) in Paris, speaking at several forums.

[16] In May 2016, the Marijuana Policy Project released a voter guide of the candidates of the four largest political parties (Democratic, Republican, Libertarian, and Green) in the 2016 election.

"[18] On June 15, 2016, the Stein campaign announced that it had received 203 delegates, enough to win the nomination on the first ballot at the 2016 Green National Convention.

Stein noted that she would seek to qualify for matching funds from the federal government by raising at least $5,000 from residents of 20 states before receiving the nomination in 2016.

[25] In September, Stein's campaign said they had met the $5,000 mark in five states (California, Florida, Massachusetts, New York, and Washington) and had received at least half of that amount in eight others.

On November 28, Richard Winger of Ballot Access News reported that Stein would likely qualify for the initial public funding before January 1, 2016.

On November 23, Stein launched a public fundraiser to pay for recounts in Wisconsin, Michigan, and Pennsylvania, in which she asserted that the election's outcome had been affected by hacking.

[40] On December 18, 2017, the Washington Post reported that the Senate Intelligence Committee would examine Stein's presidential campaign for potential "collusion with the Russians".

[42] In December 2018, two reports commissioned by the US Senate found that the Internet Research Agency boosted Stein's candidacy through social media posts, targeting African-American voters in particular.