I remember from my mumble about nine mumble rereads of the Harry Potter series that the following classes Harry took were taught to more than one house in the same lesson:

  • Potions with the Slytherins
  • Herbology with the Hufflepuffs
  • Care of Magical Creatures with the Slytherins
  • broomstick riding with at least the Slytherins (maybe other houses, too?)

I don't remember any student from a house that isn't Gryffindor being mentioned in the sections on Transfiguration, Charms, Defense Against Dark Arts, History of Magic, or Divination. That would mean McGonagall had to teach twice as many classes as Snape, if both subjects got the same number of lessons (which I think I recall).

Were any subjects other than Potions, Herbology, and Care of Magical Creatures taught to more than one house in the same lesson? And do we know why some subjects are taught to more students at the same time than others?

  • 4
    I've always assumed that all classes included all houses.
    – Joe L.
    Commented Oct 24, 2015 at 13:48
  • 1
    @Joe L. I think at one point in PoA, Harry mentions only seeing Ernie and Justin at Herbology, and not at Potions, so at least it's not all four houses at all classes. And more than 40 students also seems a bit much for one class. And there's a lot of looking at timetables and saying "we have double Potions with the Slytherins" and "Herbology with the Hufflepuffs" without mentioning the other two houses.
    – YviDe
    Commented Oct 24, 2015 at 13:55
  • I don't think it's a school policy not to mix houses in the same class, but just through scheduling and student's preferences to take classes with their friends, sometimes classes are predominately only one or two houses.
    – Joe L.
    Commented Oct 24, 2015 at 14:13
  • 1
    @Joe L. No, all students have to take the core classes (Potions, Herbology, Transfiguration, Charms, DADA, History of Magic) for the first five years. There is no choice at all until third year. And Harry has all his classes with his whole Gryffindor year for the first two years until they choose whether to take Divination / Muggle Studies / Ancient Runes / etc
    – YviDe
    Commented Oct 25, 2015 at 8:07
  • 1
    This happens in real life. To fill a class, you schedule students taking the class. If that means pulling from two houses, then do it. Also, remember, Harry has no reason to notice or care about classes he doesn’t take, where, say, Snape teaches potions to a class of Hufflepuffs and Ravenclaws.
    – Dúthomhas
    Commented May 6, 2019 at 3:46

4 Answers 4


Another example:

  • Gryffindors and Hufflepuffs share Muggle Studies classes

    Ernie Macmillan tells Harry and Ron in PoA chapter 12 that Hermione had never missed a Muggle Studies class, implying that he was taking the class together with her.

Muggle Studies is one of the optional classes, with fewer students taking it. It's plausible that all Houses are mixed in such classes (well, assuming any Slytherins take Muggle Studies!)

In post-OWL years, when there are fewer students taking any subject, more (all?) classes are mixed; for instance:

  • Gryffindor, Slytherin, and Hufflepuff (probably Ravenclaw too) share 6th-year Potions classes

    There were a total of 12 students who achieved either Outstanding or Exceeds Expectations on their Potions OWL and were able to advance to NEWT class. In HBP, the first Potions class includes Harry, Ron, Malfoy, and Ernie Macmillan; it's mentioned that Ernie is the only Hufflepuff there, which suggests all four Houses were represented.

  • Gryffindor and Slytherin share 6th-year DADA classes

    Malfoy is there to snigger at Snape's bullying of Harry and Ron during their DADA classes in HBP; we also learn that Crabbe and Goyle would have been there but failed their DADA OWLs.


There are a few instances, of varying canon status:

  • Gryffindors and Ravenclaws might share Transfiguration classes.

    Quoting Luna in Half-Blood Prince (her OWL year):

    “Oh, it's been alright. A bit lonely without the D.A. Ginny’s been nice, though. She stopped two boys in our Transfiguration class calling me ’Loony’ the other day —”

    That sounds as if they’re in the same class.

  • 3
    The Patil twins are both Gryffindor in the films though, aren't they?
    – Rand al'Thor
    Commented Oct 24, 2015 at 10:50
  • 9
    @randal'thor you're right, ffs. hits movies with a stick
    – alexwlchan
    Commented Oct 24, 2015 at 11:01
  • 6
    Yes, bloody films [grumbles] :-) Still, that means the second half of your answer doesn't work. Maybe you should edit it out?
    – Rand al'Thor
    Commented Oct 24, 2015 at 13:09

In PoA, the book lists all of the Gryffindor students' boggarts except Harry and Hermione, who are said to be the only students who did not face the boggart in the class. No one from any other house is mentioned, so this heavily implies that, in 3rd year at the very least, each class takes DADA separately.


Gryffindors share Potions with Slytherins and Herbology with Hufflepuffs and Charms with the Ravenclaws. Divinaton/Muggle studies/Arithmancy/Care of magical creatures have students from all houses. If a student chose to study the subject, they're in the class. In 6th and 7th year classes have students from all classes as they're NEWT level and have less students in them.

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