Moody Margaret, sometimes referred to as Margaret, is a fictional character and the secondary antagonist in the Horrid Henry series.
She is best known as Horrid Henry's archenemy. Margaret forms a Secret Club in her back garden, an all-female group that consists of her friends, such as Sour Susan, and occasionally Gorgeous Gurinder and Lazy Linda, this club often rivals with Henry's Purple Hand Gang, with her and Henry living next door to each other.
- Margaret lives with her parents and no siblings have been mentioned, so it's likely she is an only child, as hinted in "Moody Margaret Moves In".
- While it's uncertain on how Margaret views men, she has expressed a hateful, chauvinistic view about boys, as shown in "So Not a Girl!", the same episode that hints Susan is Margaret's "slave".
- Ironically, in "Perfect Peter's Revenge", Margaret wanted to force Henry to admit he "loved" her, due to two fake love letters his younger brother Peter sent Margaret and Susan, which would contradict the frequent rivalry between Henry and Margaret and their groups.