UNESCO's Executive Board -- on which 58 member countries have a seat -- adopted the proposal for a prize named after Teodoro Obiang Nguema Mbasogoin in 2008 and accepted the president's offer of $3 million in prize money, Sciencemag.org reported.
Although a winner had already been accepted, the board decided to postpone implementation of the award after an outcry from human rights and science groups.
Obiang has ruled Equatorial Guinea since leading a 1979 coup in which his predecessor -- his uncle -- was killed.
Obiang has been the subject of several international investigations into massive corruption, and critics charge his regime with an abysmal record on human rights.
UNESCO member countries have been split on the award, with most western countries opposed to it while African countries have for the most part supported it, leading to a stalemate in the board.
UNESCO says it has decided to suspend the prize "and continue the consultations among all parties concerned, in a spirit of mutual respect, until a consensus is reached."
Since a consensus is generally considered unattainable, it means the award will be postponed "until never," says Kenneth Hurwitz of the Open Society Justice Initiative in New York City, one of the groups that oppose the award.