Evil Teacher

So you have a cruel, mean, bully of a teacher, that's got to make school life pretty harsh right? Well it could be worse, they could actually be evil.

This includes Mooks and Murderers whose day job is teaching, all way up to Big Bads who pose as teachers as part of the Masquerade. Not too uncommon in Wake Up Go to School Save The World situations, but can also appear in other works which are set in a school or University.

Sometimes this does overlap with the Sadist Teacher but it isn't too uncommon for some iteration of supposedly "nice", and/or well liked, teacher to be secretly evil. Perhaps so secretly even they don't know.

If they don't like teaching, a Sadist Teacher can result. If they do like it, they'll often end up a Badass Teacher.

Also not to be confused with Evil Mentor, who is not only evil, but also corrupts his disciples with evil teachings.

Anime

 * Harumi Saotome of the Higa team in The Prince of Tennis. This is the guy who actually orders his pupils throw balls at the rival coaches to injure them, and throws tantrums when they don't go along with it.
 * Kuzuki of Fate Stay Night is a bit of a subversion.
 * Professor Cobra of Season 3 of Yu-Gi-Oh GX.
 * of the 2003 anime version of Fullmetal Alchemist.
 * of Shugo Chara, who is only a teacher as it involves screening children from Seiyo Academy to see if they possess the legendary "Embryo" as their "Hearts Egg". As the best way to draw out a "Hearts Egg" is to make a child become filled with self doubt about their aspirations for life, and usually means that without outside help they get their dreams crushed and he is a Child Hater, he's presented as evil.

Film

 * The Faculty
 * Kitano in Battle Royale. Although this is almost justified by the fact that the world has gone to hell and the students are unruly to the point of stabbing him at random in the hall. He doesn't actually do anything malevolent to them until after they've left school and he enrolls them in the BR program
 * Matt Dillon's character in Wild Things.
 * The Assistant Principal, and the super-teachers he hires, in Korean action-comedy Volcano High.
 * In Hot Fuzz,

Fan Fiction

 * Harry Potter fanfiction. Way too many people like to portray Dumbledore as a Manipulative Bastard Complete Monster who's setting up Harry as a Heroic Sacrifice to defeat Voldemort, in some cases with Dumbledore planning to take all the glory immediately after. A few fanfics also have him paying off Ron/Hermione/Ginny/whoever to be Harry's "friend" as a way for Dumbledore to spy on him.

Literature

 * The Demon Headmaster kinda evident from the title.
 * Harry Potter: given that it's set in a Wizarding School this isn't suprising. Most of the books had one, usually the Defense Against the Dark Arts teacher.
 * Philosophers/Sorcerers Stone -
 * Chamber Of Secrets -
 * Prisoner of Azkaban - none
 * Goblet of Fire -
 * Order of the Phoenix - Umbridge, former trope namer for Tyrant Takes the Helm, whose idea of detention involves students magically carving words into their own hands by writing lines.
 * Deathly Hallows -
 * Agatha Trunchbull in Matilda isn't just a Sadist Teacher, it becomes obvious at the end that
 * Coach Gengis - who is really Count Olaf in disguise - from A Series of Unfortunate Events. (Not spoilered because... well, it's Count Olaf we're talking about).
 * The Guardians of Time trilogy tries to do this and fails miserably.
 * As does The German Harry Potter/The Neverending Story/The Lord of the Rings knock-off The Laura Cycle
 * On of the Diamond Brothers novel Public Enemy Number Two has
 * Madame Morrible from Wicked. Both the musical and the book.
 * Miss Gaunt in Ghosts of Fear Street: Who's Been Sleeping in my Grave?.
 * Vice Principal Nero from A Series of Unfortunate Events is a true sadist. He makes Sunny (A BABY) work as his secretary, punishes people by taking away silverware and tying people's hands behind their backs during lunchtime.
 * The Teacher From The Black Lagoon and its many, many sequels would qualify as the best example if The X Files hadn't taken that honor. "This is a whole boy. This is half a boy. Now you've learned fractions."
 * Mrs. Gorf in the Wayside School series, who turned students into apples. There were several other evil teachers as well.
 * Vice-Principal Chapman from Animorphs, who's high up in the Yeerk front organization The Sharing (which is similar to a scouting group or something) and often tries to recruit students, including the protagonists. He acts like a nice guy, though.
 * Salamander features Maridon, one of the teachers in the story's College of Magic. He's not presented as a bad teacher, just as a teacher who wants to be a Person of Mass Destruction.
 * Professor James Moriarty.
 * The Young Bond novel Blood Fever has, who appears to be a Reasonable Authority Figure but it as actually a member of a secret society dedicated to restoring the Roman Empire and who poisons the teenaged James Bond when he gets to close to the truth.

Live Action TV

 * Power Rangers Dino Thunder - Principal Randall
 * Half the faculty (including a few dinner ladies) in the Doctor Who episode "School Reunion".
 * The Sarah Jane Adventures story Revenge of the Slitheen.
 * Buffy the Vampire Slayer - "Teachers Pet"
 * In season four of Buffy, there was the Knight Templar Psychology professor Maggie Walsh.
 * Ms. Paddock from the second season X-Files episode "Die Hand Die Verletzt".
 * He's only briefly a teacher, but Cromartie from The Sarah Connor Chronicles
 * In the Outer Limits episode "The Special One", Mr. Zeno, an alien in human form, tutors gifted children, planning to indoctrinate them and use their advanced scientific skills to help his planet conquer Earth. Zeno kills one father who discovers what's going on, and.
 * In Smallville Brainiac mixes this with Badass Bookworm, Complete Monster, Evil Mentor, and Omnicidal Maniac. No he's not your average History Prof.
 * The headmaster Mr. Finch and the new staff he installed in the Deffry Vale School in the Doctor Who episode "School Reunion".

Video Games

 * Persona 4 has Mr. Morooka, a.k.a "King Moron", a rather snobbish (and hideous) man with a grudge against women as well as the main character. He treats his students rudely (putting the main character on his "Shit List" within minutes of meeting him), and has a tendency to get drunk on school fieldtrips..

Web Comics

 * Angel Moxie has an evil teacher, it's also
 * The Wotch has

Western Animation

 * Aaahh Real Monsters had The Gromble.
 * Courage the Cowardly Dog: Episode 52 Part 2: "Perfect" had a mysterious old teacher approaches him, and strictly trains him into becoming a perfect dog.
 * Denzel Q. Crocker from The Fairly Odd Parents slides from a simple pathetic Sadist Teacher to truly evil depending on the episode. Compare the Sympathetic POV Crocker in "The Secret Origin of Denzel Crocker!" to the maniacal dictator he becomes in the Made for TV Movie episode Abra-Catastrophe!.
 * Headmistress from Mucha Lucha
 * Invader Zim had Miss Bitters.
 * X Men Evolution has Bayville High's Principal Darkholme . Kelly was no slouch, either, especially after mutants were exposed.
 * Miss MacBeth from Invisible Network of Kids.