Eliza Pinchley is the daughter of English conman Nigel Pinchley. Stewie tried to civilize her. His efforts eventually met with brief success, but she soon reverted back to her Cockney self by wetting herself in public. Unfortunately, after her father was hanged for insurance fraud in Britain (NB there is no capital punishment in the UK), she was sent to live in an orphanage. Blaming Lois for her ordeal, she writes a letter to Stewie saying (to Stewie's great amusement) that she will make it her life's effort to make sure that his mother suffers a vengeful and horrible death. She appeared in "One if by Clam, Two if by Sea".

Eliza is a spoof of Eliza Doolittle, originally from the George Bernard Shaw play Pygmalion which inspired the musical My Fair Lady that Seth MacFarlane claims as the source of the character. She is voiced by Tara Strong while her singing voice is provided by Michelle Horn.