| Office: | 20th United States Assistant Secretary of State for International Organization Affairs |
| President: | Bill Clinton |
| Term Start: | March 19, 1997 |
| Term End: | October 22, 1998 |
| Predecessor: | Douglas J. Bennet |
| Successor: | David Welch |
| Ambassador From1: | United States |
| Country1: | South Africa |
| Term Start1: | July 14, 1992 |
| Term End1: | December 14, 1995 |
| Predecessor1: | William Lacy Swing |
| Successor1: | James A. Joseph |
| President1: | George H. W. Bush Bill Clinton |
| Ambassador From2: | United States |
| Country2: | Nigeria |
| Term Start2: | September 12, 1986 |
| Term End2: | July 24, 1989 |
| Predecessor2: | Thomas W. M. Smith |
| Successor2: | Lannon Walker |
| President2: | Ronald Reagan George H. W. Bush |
| Birth Date: | 20 November 1935 |
| Birth Place: | San Francisco, California, U.S. |
| Death Place: | Silver Spring, Maryland, U.S. |
| Office3: | 6th Director of the Bureau of Refugee Programs |
| Term Start3: | September 5, 1989 |
| Term End3: | June 15, 1992 |
| Preceded3: | Jonathan Moore |
| Succeeded3: | Warren Zimmermann |
Princeton Nathan Lyman (November 20, 1935 – August 24, 2018)[1] was a diplomat and former United States Ambassador to Nigeria (1986–89) and South Africa (1992–95), and former Assistant Secretary of State for International Organization Affairs (1996–98[2]).[3] He was a member of the American Academy of Diplomacy and the Aspen Institute, and was Adjunct Senior Fellow for Africa Policy Studies with the Council on Foreign Relations.[4]
Lyman had a bachelor's degree from the University of California, Berkeley and a Ph.D. from Harvard University.[5]
Lyman played a crucial role in the negotiation and signing of the 1994 Accord on Afrikaner self-determination in South Africa. As the U.S. Ambassador, he skillfully mediated between General Constand Viljoen, representing Afrikaner interests, and the African National Congress (ANC). Lyman's deep understanding of South Africa's complex political landscape and his respect for Afrikaner concerns helped prevent potential conflict during the transition from apartheid, ultimately facilitating the peaceful inclusion of Afrikaners in the new South African democracy.[6]
In January, 2010, Lyman weighed in in opposition to using the U.S. Alien Tort Statute in federal court to gain reparations for South African workers, from corporations who operated in South Africa during the apartheid era.[7]
In January, 2011, Lyman, who acted for the US government in mediation talks between the north and south of Sudan, was in Sudan for the independence referendum of Southern Sudan.[8] [9]