Modesto Seara-Vazquez (born in Allariz, Spain, September 11, 1931) is a professor of international law and international relations.
For most of his career he worked at the National Autonomous University of Mexico (UNAM) and in the State of Oaxaca as founding rector of the Oaxaca State University System (OSUS).
He made important contributions to the fields of international law and international relations.
He is considered one of the founding fathers of the Outer Space Treaty because of his writings in the 1950s.
He also founded several universities, according to a model of his own design.
In Spain he was very active in politics, particularly during the political transition in the 1970s and early 1980s, but also as a student in the early 1950s, when he was a member of socialist organizations.