A monoclonal antibody produced by hybridoma cells against full-length Aequorea victoria green fluorescent protein (GFP). This antibody recognizes native and denatured forms of wild-type GFP, GFPuv, AcGFP, EGFP, destabilized EGFP variants, EBFP, EYFP, ECFP, AcGFP, and both N- and C-terminal fusion proteins containing these GFP variants in bacterial and mammalian cell lysates.