Keith Weissman is an American foreign policy expert and former lobbyist who served as a senior official at the American Israel Public Affairs Committee (AIPAC) from 1993 to 2005, holding positions including Senior Iran Analyst and later Director of Foreign Policy (also described as foreign policy director and Iran specialist). He specialized in Middle East policy, particularly issues related to Iran, Persian Gulf affairs, and Israeli security, building extensive relationships with U.S. government officials, members of Congress, and Pentagon staff to advocate for pro-Israel policies such as sanctions against Iran and opposition to the Iran nuclear deal. His work involved monitoring and influencing U.S. foreign policy on behalf of AIPAC's interests, engaging with policymakers on sensitive national security matters, and he was known for his expertise on Iranian nuclear ambitions and regional security.

In August 2005, Weissman and his AIPAC colleague Steve Rosen were indicted by a federal grand jury on charges of conspiracy to communicate classified national defense information to unauthorized persons, in violation of the Espionage Act (18 U.S.C. § 793), in what became known as the AIPAC espionage scandal or the 2005 spying allegations (also referred to as the Franklin case). The case stemmed from their interactions with Pentagon analyst Larry Franklin, who pleaded guilty to passing classified information about U.S. policy on Iran to Weissman and Rosen, who then allegedly shared it with Israeli diplomats and journalists. The charges drew significant attention to pro-Israel lobbying activities and highlighted tensions between advocacy and national security.

In 2009, the charges against Weissman were dismissed by a federal judge after a prolonged legal battle, with the court citing insufficient evidence, vagueness in the law, and constitutional protections for lobbying activities (including First Amendment concerns). Following his departure from AIPAC in 2005 amid the investigation, Weissman joined the Washington Institute for Near East Policy (WINEP) as a senior fellow, continuing his work on Iran and Middle East policy analysis. He has been quoted in media on foreign policy matters, contributed to policy debates, and has been the subject of books and reports critical of pro-Israel lobbying. Weissman's career highlights his role in shaping U.S. foreign policy discourse on Israel and Iran, amid ongoing controversies over influence, transparency in lobbying, and the blurring of lines between advocacy and intelligence handling. The case remains a notable chapter in discussions of U.S.-Israel relations, foreign influence, lobbying ethics, and intelligence handling.