Blau is an uncommon Jewish surname with origins in western Romania and Poland. Fur traders hunted arctic foxes for their blaufuchsfell, blue fox fur, and adopted the names Blaufuchs, Blaufuks, and Blaufück. These surnames were later shortened to Blau. Notable people with the surname include:
Alfred Blau (died 1896), French dramatist and opera librettistAmram Blau, Israeli Neturei Karta rabbiDaniel Blaufuks, a Portuguese photographerDick Blau (born 1943), Professor of Film at the University of Wisconsin-MilwaukeeÉdouard Blau (1836–1906), French dramatist and opera librettistEric Blau (1921–2009), creator of the Off Broadway show Jacques Brel is Alive and Well and Living in ParisFreda Meissner-Blau (born 1927), Austrian politician, activist, and founder and the federal spokesperson of the Austrian Green PartyHarry Blau (1885–1945), Latvian sports shooterHerbert Blau (1926–2013), director and theoretician of performanceHermann Blau (1871–1944), German engineer and chemist, and inventor of Blau gasJoseph Leon Blau (1909–1986), American scholar of Jewish history and philosophyKarl Blau, American musicianLajos Bíró (born Blau), (1880–1948), Hungarian novelist, playwright, and screenwriterLajos Blau, Hungarian scholar and publicistLeslie Blau, author, historian, and survivor of the HolocaustMarietta Blau (1894–1970), Austrian physicistMax Blau (1918–1984), Swiss chessPeter Blau (1918–2002), Austrian Jewish sociologistRachel Blau DuPlessis (born 1941), American poet and essayistRaphael Blau (1912–1996), American screenwriterRolf Blau (born 1952), retired German football midfielderTheodore H. Blau (1928–2003), clinical, police and forensic psychologist who was the first clinician in independent practice to be elected president of the American Psychological Association in 1977Tina Blau (1845–1916), Austrian painterUri Blau (born 1977), Israeli journalist and investigative reporterYaakov Blau (1929–2013), Israeli rabbiYosef Blau, president of the Religious Zionists of America and serves as the Mashgiach ruchani at Rabbi Isaac Elchanan Theological Seminary