Fartypants Fiona is a girl in Horry Henry's class at Bashtoun School. She has always had a reputation of doing bad farts in class and blaming them on someone else. Fiona also frequently eats at Gobble n' Go which might be the reason for her constant farting. Fiona's farts also smell like old cheese and occasionally rotten eggs.

Unfortunately, Fiona is considered to be the worst character of the entire Horry Henry series, due to unlikable personality, predictable jokes, and has a voice that sounds high-pitched. As a result, she has never made an appearance in Series 2 (aside from Horry Henry Thinks Big) and beyond.