- Author Existence Failure: Miyu Matsuki, Isumi Saginomiya's JP voice actress, died from lymphoma on October 27, 2015.
- Crossdressing Voices: Ryoko Shiraishi provides the Japanese voiceover for Hayate.
- Fan Nickname:
- Nishizawa -> NOM NOM, since she's always eating…
- Her fans like to call Athena 'A-Tan', despite the fact that it destroyed a seemingly strong bond of friendship within the story. It's well implied that Athena only wants Hayate to use the name.
- What Could Have Been:
- Originally the author had written a one-shot manga about a high school student and her sister dealing with a debt. These characters became Yukiji and Hinagiku.
- Bonus chapters say there was a big reveal planned around Maria's family. Namely that she's actually Hayate's half sister, forcing him to deal with the fact he has a crush on someone in his own family.
- The original ending to the hiking arc in volumes 14-15 was cut because another manga at the same time had an identical joke by a freak coincidence.
- The Wiki Rule: There's a wiki for the series canon.
Trivia / Hayate the Combat Butler