Julissa Reynoso Pantaleón (born January 2, 1975) is a Dominican-American attorney and diplomat. She is the current chief of staff to First Lady Jill Biden. She formerly served as a litigation and international arbitration partner with the international law firm Winston & Strawn LLP. She was previously a partner with Chadbourne & Parke LLP, practicing in the firm's International Arbitration and Latin America groups. Reynoso is also affiliated with the faculty at Columbia University School of Law and the School of International and Public Affairs. From March 2012 until December 2014, she served as United States ambassador to Uruguay. She is a former deputy assistant secretary for the Bureau of Western Hemisphere Affairs at the United States Department of State.