GJB can refer to:
George Jackson Brigade, American activist group Gap junction β, subcategory of gap junction proteins Good Job, Brain!, English-language trivia podcast Trans-Air-Link, defunct airline with its hub at Miami–Opa Locka Airport in Miami-Dade County, Florida, U.S.; see List of defunct airlines of the United States (Q–Z)#T
See also GJB 5860-2006, Chinese military technical standard