Au or AU may refer to:

AU TICKETS BTS Tickets Rush Tickets Journey Tickets Shakira Tickets Bryson Tiller Tickets Earth, Wind and Fire Tickets

Science

• Absorbance Units, a reporting unit in spectroscopy
• Astronomical unit, the average distance between the Earth and the Sun (roughly speaking)
• Atomic units, a system of units convenient for atomic physics and other fields
• Gold, a chemical element with the symbol Au
• a.u., abbreviation for arbitrary unit

Computing

• .au, the internet country code for Australia
• Au file format, Sun Microsystems' audio format
• Audio Units, a system level plug-in architecture from Apple Computer

Universities

• Aarhus University, Denmark
• Aberystwyth University, Wales, United Kingdom (a founding member of the University of Wales in 1877, left the federation in 2007)
• Adelphi University, New York, United States
• Alfred University, New York, United States
• Algoma University, Sault Ste. Marie, ON, Canada
• Allahabad University, Uttar Pradesh, India
• American University, Washington, DC, United States
• Andrews University, Michigan, United States
• Anderson University (Indiana), United States
• Anderson University (South Carolina), United States
• Arellano University, Philippines
• Athabasca University, Alberta, Canada
• Auburn University, Alabama, United States

Geography

• Australia
• Au (Munich), Munich, Germany
• Au (Schwarzwald), Baden-Wurttmberg, Germany
• Au am Leithaberge, Austria
• Au am Rhein, Germany
• Au, Guinea, Kankan Region
• Au im Bregenzerwald, Austria
• Au in der Hallertau, Germany
• Au peninsula, Switzerland
• Au, St. Gallen, Switzerland
• Au, Vorarlberg, Bregenz, Austria
• Au, Zurich, Switzerland

Organizations

• African Union
• au (mobile phone operator), a mobile phone operator in Japan
• Akademia Umiejetnosci, a primary Polish scientific institution
• Americans United for Separation of Church and State
• Austral Lineas Aereas, IATA code
• Adventure Unlimited

Miscellaneous

• Ab urbe condita (sometimes abbreviated as a.u.), Latin for "from the founding of the City" (Rome)
• Au (squat), a building that has been squatted in Frankfurt, Germany
• Aú, a cartwheel in the Brazilian martial art of Capoeira
• Au (surname), a Chinese family name
• Au Co, a fairy in Vietnamese mythology
• Au (band), an experimental pop group headed by Luke Wyland
• Ford AU Falcon, a family car made in Australia
• Alternative Ulster , a music magazine
• Alternative universe (fan fiction)
• Athletic Union, the union of sports clubs in a British university