I thought this was a tough one; I added many characters who I think are underrated (and a few who I think are overrated, just for good measure XD). But I'd say it'd have to be Ron.

Compared to the other members of the Golden Trio, Ron gets very little appreciation, even though he is every bit as important and spectacular and amazing as Harry and Hermione. He is overlooked by the fans. He is overlooked by his peers in the books. He is even overlooked in the movies (well, maybe not the first three or four, but certainly from then on), shoved to the background until he is no more than a side character, or, at best, the comic relief. He deserves better.

I love Ron Weasley <3

and ginny

and McGonagall

Ron all the way, out of the Trio he is Underrated,and here is even Luna more popular,so Ron is that for me,then Mcgonagall and Lupin Love them both

McGonagall is way underrated.She is one of my favourites.but in the movies she is largely neglected which makes me MAD.Ron too is left out in the movies....

McGonagall too they both deserve more credit then they're given.

no one gives him credit

Agree with roseteaxx.

Cho-everyone always hates on her-it gets on my wick!

She is sooo cool.Ron is very popular...

and Flitwick

Ron and Ginny? Are you people kidding me? I say Cho and Remus. No one ever thinks of them.

And McGonagall.

Okay, I love, love, love, love Seamus!!! I wish he was in the movies more!

well i just think shes underrated..shes co cool.

how the hell ron is underrated he's the most overrated character in HP movies and books

^Because in the films he's relegated to the comic relief, and every other contribution he originally had is either omitted or transferred to Hermione.