Protista kalma ce ta ilmin halitta da ke nufin wata masarauta a cikin tsarin rarraba rayayyun halittu. Ƙungiya ce daban-daban na ƙananan ƙwayoyin eukaryotic waɗanda ba su dace da nau'ikan tsire-tsire, dabbobi, ko fungi ba. Kalmar “protista” ta fito ne daga kalmar Helenanci “protistos,” ma’ana “na farko.”Protists suna nuna halaye da salon rayuwa iri-iri. Suna iya zama unicellular ko multicellular, da kuma wasu nau'ikan mallaka. Masarautar Protista ta ƙunshi nau'ikan halittu iri-iri kamar algae, amoebas, ciliates, slime molds, da protozoans. Ana iya samun waɗannan kwayoyin halitta a wurare daban-daban, waɗanda suka haɗa da ruwa mai laushi, yanayin ruwa, da kuma wurare masu ɗanɗano na ƙasa.A matsayin masarauta, ana ɗaukar Protista a matsayin rukuni na paraphyletic, ma'ana ya haɗa da wasu, amma ba duka ba, zuriyar wata ƙasa ce. gama gari. Wannan saboda protists ba ƙungiyar monophyletic ba ne kuma ba sa raba kakanni ɗaya na kwanan nan keɓanta na sauran eukaryotes. Koyaya, har yanzu ana gane masarautar Protista azaman rarrabuwa mai dacewa ga kwayoyin halitta waɗanda basu dace da sauran masarautu ba.