Open Philanthropy is a research and grantmaking foundation that makes grants based on the principles of effective altruism.

Its current chief executive officer is Alexander Berger, and its main funders are Cari Tuna and Dustin Moskovitz.

[3][4] Tuna left her journalist position at The Wall Street Journal[4] to focus on philanthropy full-time,[3] and the couple started the Good Ventures foundation in 2011.

More recently, Open Philanthropy has pushed to identify causes that could leverage funding to “get more humanitarian impact per dollar”, leading to the creation of several new programs (in areas such as public health and innovation policy) and leaving GiveWell as a smaller portion of the portfolio.

[19] Open Philanthropy's investments in global health and development include efforts to cure iodine deficiencies, prevent malaria,[20][21] and scale up vaccine production.

[40] On the 80,000 Hours podcast, whose largest funder is Open Philanthropy, some biosecurity experts, however, have anonymously counseled against "failures of imagination", overreliance on historical precedents, and other ways of thinking that could lead people to underestimate catastrophic biorisk.

[41] Grants in this portfolio include: Past focus areas of Open Philanthropy have included criminal justice reform (which spun out as a new organization in 2021[49]) and US macroeconomic stabilization policy (which ceased to be a focus in 2021,[50] though European macroeconomic policy grants have been made more recently).