Issue One is an American nonprofit organization that seeks to reduce the role of money in politics. It aims to increase public awareness of what it views as problems within the present campaign finance system, and to reduce the influence of money in politics through enactment of campaign finance reform.

Issue One was formed in October 2014 through the merger of two campaign finance reform organizations: Americans for Campaign Reform and Fund for the Republic.

Americans for Campaign Reform, which was formed in 2003, had been focused on issues related to campaigns and elections, including pushing for public funding for federal and state elections. Fund for the Republic, which was formed in 2012, aimed to remove the use of big money and dark money in American politics. Issue One combined these initiatives.

Issue One's stated mission is "fighting to protect U.S. elections, lessen political polarization, limit the influence of big money over politics, and improve the ability of Congress to solve problems." The organization raises awareness about these issues, advocates for legislation and federal action, and produces research and analysis related to key issues.

In 2015, Issue One launched the ReFormers Caucus, a bipartisan group of former lawmakers advocating for campaign finance reform. The caucus initially included more than 100 former officeholders, including former Senate Majority Leader Tom Daschle, former Utah governor Jon Huntsman, and former Secretary of Defense Leon Panetta. By 2019, that number had expanded to more than 200 members.

The ReFormers Caucus has proposed increasing civic participation, passing laws that define and regulate the role of money in federal elections and "boosting small donations to campaigns, finding ways to restrict political contributions from lobbyists and unmasking secret contributions made to tax-exempt groups that are active in politics."

A January 2022 report from Issue One titled "Fair Pay: Why Congress Needs to Invest in Junior Staff" found that one in eight congressional staffers in Washington, DC, were not paid a living wage. The report showed that entry-level staff, in particular, were earning 30 percent less than the national average salary, and recommended a salary floor for all Hill staffers. In April 2022, the Congressional Hispanic Staff Association published an open letter to both chambers of Congress asking for immediate salary increases for staff, citing Issue One's report on the issue.

In 2020, Issue One launched the National Council on Election Integrity to counter disinformation about the 2020 United States presidential election and ensure a peaceful transfer of power. The council was bipartisan, with members including former Democratic National Committee chair Donna Brazile, former Secretary of State Madeleine Albright, former Senator and Director of National Intelligence Dan Coats, former Senate Majority Leader Bill Frist, and two former Defense Secretaries, Republican Chuck Hagel and Democrat Leon Panetta.