Gau or GAU may refer to:

• Gaugericus (c. 550–626), Bishop of Cambrai
• Gau Ming-Ho (born 1949), Chinese mountaineer
• Franz Christian Gau (1790–1854), German architect and archaeologist
• James Gau (born 1957), Papua New Guinean politician
• Michael Gau, Taiwanese political office-holder
• Susan Shur-Fen Gau (born 1962), Taiwanese psychiatrist

• Gäu, name of the South German loess landscapes
• Gau (territory), German term for a shire (regional administration)
• An Administrative division of Nazi Germany
• Gäu (Baden-Württemberg), a region in the southwest German state of Baden-Württemberg
• Gaū, Iran, a village in Sistan and Baluchestan Province
• Gäu District, district of Solothurn, Switzerland
• Gau Island, an island in Fiji
• Gau Airport
• Lokpriya Gopinath Bordoloi International Airport (IATA code: GAU), in Guwahati, Assam, India

• Georgetown American University, in Guyana
• Girne American University, in Northern Cyprus
• Gujarat Ayurved University, in India
• University of Göttingen (German: Georg-August-Universität Göttingen), in Germany

• Gau (Final Fantasy VI), a character in Final Fantasy VI
• GAU, a codon for the amino acid aspartic acid
• Gouais blanc, a French wine grape
• Enfariné noir, a French wine grape
• General Assistance Unemployable, a Washington state unemployment program
• Kondekor, a variety of the Ollari language with ISO 639-3 code gau
• Gau, a Cantonese vulgar word
• Glavnoe Artilleriyskoe Upravlenie, a division of the Russian military that played a significant role in the history of radar

• Gau Mata, sacred cows in Hinduism
• All pages with titles beginning with Gau