Lisping Lily is a toddler in Horrid Henry's Sleepover and Perfect Peter's Pirate Party. She loves Horrid Henry, as Henry thinks "Ewwwww..." She is New Nick's worst sister. Her common catchphrases in the book are "I Love you, Henwy." and "Will you marry with me Henwy?" She appears again in Perfect Peter's Pirate Party where she tries to ask Henry to marry again only to costume. She possibly wants to kiss Henry, as in Horrid Henry's Sleepover. "I want to give you a big kiss, Henwy,"
She is also the subject of a joke in Horrid Henry's Jolly Joke Book. Nick asks Henry if he thinks his sister is pretty, Henry says that if you pulled her pigtails she'd probably say "Oink! Oink!". She wears a dummy, a blue bow and blue dungarees.