The ↗Happy Lesson franchise:
- (2001) Happy Lesson OAV (5 OVA episodes)
- (2002) Happy Lesson TV (reboot/sequel, 13 TV episodes)
- (2002) Happy Lesson Mini (short side stories, DVD omake)
- (2003) Happy Lesson Advance (sequel, 13 TV episodes)
- (2004) Happy Lesson the Final (conclusion, 3 OVA episodes)