Checking Wikipedia, I find that most of the animated Spider-Man shows have mentioned it.
Don’t know the mascot.
Chancellor Edward Gorman has been mentioned in the comics.
Also one of the few TV schools where the motto is known: E Pluribus Flamingus.
Yeah, that makes sense.:dubious:
(I don’t even know what the motto of my high school was, or if it had one.)
“Out of many, Flamingo!” 
When PLCL was on Fox, I saw an interview with Melanie (Principal Musso) Chartoff, where she said dozens of kids would stop her on the street and request she do the “Thumb Whoosh.” She was seriously considering getting one of those** That Was Easy** buttons and having it doctored to make the sound. 
Millard Fillmore High School in Manhattan, from Head of the Class. Dr. Harold Samuels was the principal (had to look that up).
The school in Kick Ass has the same name and location, but I don’t know if it’s supposed to be the same school or if it’s coincidence.
DARIA,Lawndale High, Principal Ms Li, mascot a Lion.
California Institute of Science (Cal Sci)/Never specified/Never specified (NUMB3RS)
The Brady Bunch kids attended Clinton Elementary, Fillmore Junior High, and Westdale High.
I’m not sure if any principals were identified, but the Westdale mascot was the Bears (“One, two, tell me who are you? The Bears!..”)
On the MTV series Awkward., the characters attended Palos Hills High School, while on another MTV series called Faking It, they attended Hester High School.
Wagstaff School -Whalers-Principal Spoors- Bob’s Burgers
The kids in The Wonder Years attended Robert F. Kennedy Junior High for the first few seasons. The Vice Principal was Mr. Diperna; I don’t think the actual principal was mentioned. I don’t recall if the mascot was identified; I imagine it must have at least appeared in the background in some scenes at least, though.
I don’t remember the name of the high school Kevin went to in the later seasons.
The Simpsons also has the infamous Springfield Heights Institute of Technology and the Springfield Elementary… My Dear Watson Detective School.
I cheated and looked it up but:
Highland High School, ?, Principal McVicker - Beavis and Butthead
On the UK series Skins, the characters attended Roundview College, a sixth-form school (meaning, I think, the equivalent of junior and senior year of high school in American terms). And on The Inbetweeners, the characters attended Rudge Park Comprehensive.
Including UK TV programmes there’s obviously Grange Hill. A school… soap, is the best word for it, I guess. Lots gritty drama, occasionally humour, dealt with the issue of the day. It was called Grange Hill after an area on the outskirts of East London. It was geographical name.
It annoyed me when they moved it to Liverpool so they could continue not having as many non-white people in it but kept the name.
Mrs McClusky is the one I most remember from my youth. For mascots, Zammo might count. 
Eastenders also has Walford High and King Edward Secondary School.
There’s also Coal Hill School from Doctor Who and the short-lived spin-off called Class.
Two from a couple of my favorite cartoons from the early 2000’s:
Third Street Elementary School, from Recess
X Middle School, from Fillmore! (mascot: Lobstee the Lobster)
Maybe the first high school on TV:
Central High School, Principal Nettleton. I don’t recall the team’s name but they sure got Webster High’s goat in The Many Loves of Dobie Gillis.
More animated:
Echo Creek Academy, Awesome Possums, Principal Edwin Bonner-Skeeves (Star vs the Forces of Evil)
Harry Herpson High School, The Harry Herpson Herpsons, Gene Vagina (Rick and Morty)
Tom Landry Middle School, Longhorns, Carl Moss (King of the Hill)
Whitney High School - The Greatest American Hero. Mascot and principal unknown.
Yeah, it’s kind of an Easter egg-oid bit of trivia. I learned about it here on the Dope.