Sérgio Mascarenhas de Oliveira (May 2, 1928 — May 31, 2021) was a Brazilian experimental physicist, educator and scientific leader. He was awarded several prizes including the Brazilian Order of Scientific Merit in the categories of Commander and Great Cross, the for General Science, the and the Guggenheim Fellowship. Mascarenhas contributed to the creation of important Brazilian research institutions, such as the farming instrumentation center of the Brazilian Agricultural Research Corporation and the Federal University of São Carlos.