Jessica is the oldest and only daughter of Veronica and Jim Lyons as well as Jacob's older sister and is the big helper when it comes to Jacob's health like when he has the flu or a cold. Jessica is often called Jill by her school friends and doesn't mind her brother calling her that but Jacob prefers calling her Jessica, though there are times where he calls her Jill and gets mad. She is very pretty and is always being hit by some guy which she does not like him at all and she is never going to date any guy because she always hangs with her brother. She is always concerned if he is hurt or when he is in the hospital and is often bringing his Gameboy Color or share her journal with him to share how she feels about being his sister. Jessica and Jacob get along pretty well and never argue and even gave him advice on how to make Daphne like him though he was being himself and Daphne liked him back. She goes to Jacob's and Daphne's wedding. She currently works as a Assistant District Attorney helping her mother working until she was ready to be an attorney herself and in case if Jacob was in trouble she would help him in out in school which she was suppose to go to until she was writen off the attendce board.