The University of California, Santa Barbara, commonly known as UCSB or UC Santa Barbara, is a public research university and one of the 10 general campuses of the University of California system. The main campus is located on a 1,022-acre (414 ha) site in Goleta, California, United States, 8 miles (13 km) from Santa Barbara and 100 miles (160 km) northwest of Los Angeles. Founded in 1891 as an independent teachers' college, UCSB joined the University of California system in 1944 and is the third-oldest general-education campus in the system.

UCSB is a comprehensive doctoral university and is organized into five colleges offering 87 undergraduate degrees and 55 graduate degrees. The campus is the 5th-largest in the UC system by enrollment with 19,800 undergraduate and 3,050 graduate students. The university granted 5,442 bachelors, 576 masters, and 310 Ph.D. degrees in 2006–2007. In 2010, UCSB was ranked 39th among "National Universities" by U.S. News & World Report, and 29th worldwide by the Times Higher Education World University Rankings. The Academic Ranking of World Universities ranked UCSB 33rd overall, 18th in Sciences, and 15th in Engineering. In 2011, UCSB was ranked 118th internationally in the QS World University Rankings.

UC Santa Barbara is a "very high activity" research university and spent $191.2 million on research expenditures in the 2007 fiscal year, 97th-largest in the United States. UCSB houses twelve national research centers, including the renowned Kavli Institute for Theoretical Physics. UCSB faculty includes five Nobel Prize laureates, one Fields Medalist, 29 members of the National Academy of Sciences, 27 members of the National Academy of Engineering, and 23 members of the American Academy of Arts and Sciences. UCSB was elected to the Association of American Universities in 1995. UCSB was the #3 host on the ARPAnet.

The UC Santa Barbara Gauchos compete in the NCAA Division I Big West Conference. The Gauchos have won NCAA national championships in men's soccer and men's water polo.