Alliance Defending Freedom (ADF), formerly known as the Alliance Defense Fund, is an American 501(c)(3) nonprofit conservative Christian legal advocacy organization founded in 1994 by leaders including Dr. Bill Bright, Larry Burkett, Dr. James C. Dobson, Dr. D. James Kennedy, and Marlin Maddoux. Headquartered in Scottsdale, Arizona, ADF litigates on high-profile cases involving issues such as religious liberty, abortion, and LGBTQ+ rights, advocating for religious freedom, free speech, the sanctity of life, parental rights, and what it describes as God's design for marriage and family. It has built a network of over 4,100 church and ministry members, more than 3,100 allied attorneys, and 58 staff attorneys, achieving a reported 77-80% win rate in cases. As of 2025, Kristen Waggoner serves as CEO, president, and chief counsel. ADF has been involved in 83 U.S. Supreme Court cases, directly winning 16 since 2011, including key victories on religious liberty, abortion restrictions (e.g., supporting Hobby Lobby in 2014 and Mississippi in Dobbs v. Jackson in 2022), and challenges to LGBTQ rights and anti-discrimination laws. The organization is known for collaborating with the ACLJ.

ADF operates internationally through ADF International, headquartered in Vienna, Austria, with activities in over 100 countries and affiliates in India (ADF India since 2012), Belgium, Germany, France, Switzerland, the United Kingdom, and others. It has engaged in over 500 cases before national and international tribunals by 2015, reporting 580 ongoing matters in 51 countries as of 2017, with a global budget of $11.5 million in 2020-2021. The group lobbies the European Union Parliament and has presented on issues like Christian persecution, influencing foreign courts and governments on religious liberty and anti-LGBTQ policies. Notable figures associated with ADF include U.S. House Speaker Mike Johnson (former attorney), Supreme Court Justice Amy Coney Barrett, and former officials like Mike Pence, William Barr, Jeff Sessions, and Josh Hawley.

ADF has faced criticism and been designated an anti-LGBTQ hate group by the Southern Poverty Law Center due to its opposition to same-sex marriage, transgender rights, and related policies. It has been involved in high-profile culture war cases challenging abortion access, contraception mandates, gay and transgender rights, and public funding for religious schools. The organization emphasizes alliance-building among Christians, attorneys, legislators, and advocates to advance its agenda.