Inspired by comments from 10 Most Rewatchable Shonen Anime Series, Ranked
Here are a few examples that I know of:
| title | expected | actual |
|---|---|---|
| Frieren | non-shounen (seinen?) | shounen |
| Attack on Titan | seinen | shounen |
| The Apothecary Diaries | shoujo | seinen |
| Umamusume: Cinderella Gray | shounen | seinen |
| 100 Girlfriends | shounen | seinen |
What are other instances of misidentified demographic you have seen?
Quick and dirty definitions of anime demographics:
- shoujo - girls
- shounen - boys
- josei - ladies
- seinen - men


I remember reading about Minky Momo in Patrick W. Galbraith’s book. I thought it was pretty funny:
"In a personal interview, producer Satō Toshihiko recalled his surprise at encountering “male” shōjo fans attracted to Magical Princess Minky Momo and its eponymous heroine:
‘The anime started in spring 1982 and these guys started showing up after about six months. It was completely unexpected, but this guy came to our studio asking for permission to make something for his fan club. I was shocked! He told me that he was the head of this fan club, which was made up of members between eighteen and thirty years of age. He told me that he was attracted to the character Minky Momo. He thought that she was cute. It is still hard for me to understand. Minky Momo is cute, yes, and she is someone that everyone likes. I expected this response from five-year-old girls and their mothers, who might be watching the anime with them, but not adult men.’"
Galbraith, Patrick W. Otaku and the Struggle for Imagination in Japan. Duke University Press, 2019. https://doi.org/10.1515/9781478007012.