Sebastião do Rego Barros Netto (January 27, 1940 – November 9, 2015) was a Brazilian lawyer and diplomat. He served as Brazil's last Ambassador to the Soviet Union from January 26, 1990, until the country's dissolution on December 26, 1991. Following the collapse of the Soviet Union, he served as Brazil's first post-Soviet Ambassador to both Russia and Ukraine from December 1991 until December 1994. His final diplomatic posting was as Ambassador to Argentina from January 26, 1999, until December 27, 2001.