Abby Sciuto is a fictional character.
Abigail `` Abby '' Sciuto [ ˈʃuːtoʊ ] is a fictional character from the NCIS television series on CBS Television , and is portrayed by Pauley Perrette . Like Jethro Gibbs , Anthony DiNozzo , and Dr. Donald Mallard , Abby was first introduced in the episodes `` Ice Queen '' and `` Meltdown '' of the television show JAG ( which together served as the backdoor pilot for NCIS ) , and has appeared in every episode of NCIS , in addition to being featured on the show 's spin-offs , NCIS : Los Angeles ( two episodes ) and NCIS : New Orleans ( two episodes ) .