Open Primaries is an advocacy political group which advocates for “open primaries” in which voters are not required to be a member of a political party to vote for a party’s nominee. The organization lobbies, organizes ballots, and runs voter mobilization campaigns to convert both states and cities to open-primary systems. It also gives grants to numerous state- and local-level left-of-center advocacy groups that share its political goals.
Open Primaries has a 501(c)(3) educational component, the Open Primaries Education Fund, which conducts and publishes research.
Currently there are 16 states with fully open primaries, while 13 states and Washington, D.C. use completely closed primaries.  Open Primaries is running five separate campaigns with independent local organizations to introduce open primaries in states and cities:
- Alaska – Alaskans for Better Elections
- Florida – Florida Fair and Open Primaries
- Pennsylvania – Open Primaries PA
- Maine – Open Primaries Maine
- Louis – STL Approves Initiative
President John Opdycke has worked for independent and radical-left political candidates and organizations throughout his career. In the late 1980s, he worked as a researcher for the lobbying arm of the Rainbow Coalition, a left-of-center political alliance organized by Jesse Jackson. In 1992, he worked on the presidential campaign of Lenora Fulani, an avowed Marxist of the New Alliance Party.  Opdycke then worked for Fulani again two years later when she unsuccessfully opposed Gov. Mario Cuomo (D-NY) in the New York Democratic gubernatorial primary. In 1994, he also co-founded the New York State Independent Party, the state-level affiliate of the National Reform Party. 
In 1998, Opdycke became the executive director of independentvoting.org, a left-of-center campaign finance reform advocacy group to which Open Primaries gave substantial grants to after Opdycke became its president in 2014. 
Opdycke is also a founding board member of the National Association of Nonpartisan Reformers, a nonprofit seeking to enact political reforms to boost third parties. 
Senior vice president Jeremy Gruber has also worked for numerous left-of-center political causes and organizations. He was the president and executive director at the Council for Responsible Genetics, an advocacy group that demands restrictions on genetically modified foods and opposes genetics-based discrimination. Gruber was also a field director for the ACLU’s National Taskforce on Civil Liberties in the Workplace. 
Open Primaries gives grants to numerous state and local-level open primary advocacy organizations. In 2016, Open Primaries gave $1,143,448 to South Dakotans for a Nonpartisan Democracy, and $250,000 to Let Colorado Vote. The same year, it donated to three left-of-center national organizations that advocate for electoral reforms and campaign finance regulations. Open Primaries gave $75,000 to takeitback.org, $712,000 to Open and Honest Elections, and $177,297 to independentvoting.org.  Open Primaries president John Opdycke was the executive director of independentvoting.org from 1998 to 2014. 
Open Primaries’s revenue consistently reached $3.5 million from 2014-2016, but fell to $1.3 million in 2017.  In 2017, Open Primaries only gave one grant, $155,000 to Open Primaries South Dakota.