GCA may refer to:

Education

;Cayman Islands

  • Grace Christian Academy (Cayman Islands)

;India

  • Government College, Ajmer, Rajasthan
  • Guwahati College of Architecture, in Assam

;United Kingdom

  • Greig City Academy, in London

;United States

  • Gahanna Christian Academy, in Columbus, Ohio
  • Garland Christian Academy, in Garland, Texas
  • Georgia-Cumberland Academy, in Calhoun, Georgia
  • Global Communications Academy, in Hartford, Connecticut
  • Granville Christian Academy, in Granville, Ohio
  • Greenbrier Christian Academy, in Chesapeake, Virginia

Science and mathematics

  • GCA (gene)
  • Generalized Clifford algebra
  • Geochimica et Cosmochimica Acta, a scientific journal
  • Giant-cell arteritis
  • GCA, a codon for the amino acid alanine

Sport

  • Geelong Cricket Association, in Australia
  • Goa Cricket Association, in India
  • Gujarat Cricket Association, in India

Other uses

  • Garden Centers of America, an American trade organization
  • GCA Airlines, a Colombia airline
  • GCA Games Convention Asia, a video game and interactive technology convention
  • GCA Savvian, an American investment bank
  • Giant cell arteritis, a disorder
  • Global Center on Adaptation, an international organization aiming to accelerate climate change adaptation solutions
  • Goodreads Choice Awards, book awards
  • Gothenburg City Airport, in Sweden
  • Grand Canyon Association, an American fundraising organization
  • Grand Central Airport (United States), a former airport in Glendale, California, United States
  • Grand China Air, a Chinese airline
  • The Great Canadian Appathon, a Canadian game design and development competition
  • Great Commission Association, an association of evangelical Christian churches
  • Greek Cypriot Administration of Southern Cyprus, a name used for the internationally recognized Republic of Cyprus by Turkey since they do not recognize it
  • The Greeting Card Association, a British trade organization
  • Ground-controlled approach
  • Groceries Code Adjudicator, in the United Kingdom
  • Gun Control Act of 1968, a U.S. federal law
  • Gun Control Australia, an Australian lobbying group
  • Greater Central Asia, a region of Eurasia