Apathetic Teacher

There are Badass Teachers, and Sadist Teachers, and Cool Teachers, and Fired Teachers, and then there's this guy. Jaded, misanthropic, Deadpan Snarker material, this is the teacher who's been in the job too long. He dislikes students—he's been there long enough to know they're thick and (usually) irritating. He hates the school, he hates the job, he really hates the management—but because he's known virtually nothing else, he still sticks at it, putting himself through it year after year.

Sometimes, these started out as young, enthusiastic Cool Teachers, who got beaten down by rowdy kids and an uncaring system. There's usually one person who will find that their no-longer-gives-a-shit attitude makes them a Cool Teacher anyway, or at the very least an occasional confidant. They're likely to seek solace in the bottom of a bottle.

In pretty much all Save Our Students movies, one of these (if not an entire school of them) will serve as a foil to the idealistic teacher. If the school is an inner city one, expect this teacher to be the one to make some remark about how they can't really expect anything from kids with this "background."

The key difference between Apathetic Teachers and Sadist Teachers is the latter hate their students, while the former hate their jobs. Sadist Teachers often seem to take a sick glee in torturing their students; the teachers this trope describes don't seem to take much joy in anything, at least not at work.

In psychology, these people are called "burnouts".

Examples of Apathetic Teacher include:

Anime and Manga

Yukari from Azumanga Daioh gets bored with her job easily. The show's opening even shows her sleeping at her desk.
- And with disturbing frequency turns into the Sadist Teacher and abuses her students for such things as "going on vacation with his parents" or being shorter than the rest of the students.
Ms. Igurashi from Pani Poni Dash! cares less for her students than where her next drink will come from.
Reiji from Haré+Guu, as a result of his all-night anime marathons.

Film

Mr Weston from To Sir, With Love.
Dewey from School of Rock started out like this, despite being only a substitute teacher.
Mr. Turkentine from Willy Wonka And The Chocolate Factory, even though his appearance was short, seems to fall into this, what with his having no qualms about letting his students handle dangerous chemicals, or dismissing class so he can go buy Wonka Bars.

"I've decided to switch our Friday schedule to Monday, so the test we've taken on Friday over what we've learned during the week will now take place on Monday before we've learned it. But since today is Tuesday, it doesn't matter in the slightest."

Stand and Deliver
Freedom Writers
The Blind Side (particularly the male teacher)
In Puff the Magic Dragon and the Incredible Mr. Nobody, Puff shows Terry that his teacher (who put down his artistic skills) is just one of these.
The Hangover: In an amusing subversion of the Hot Teacher, Phil (Bradley Cooper) doesn't seem to care about his job or the kids at all. He is pretty much a Jerkass in general, really. In fact, you see him taking field trip money from the kids for his trip to Vegas.

Phil: (leaving for the weekend from school) Let's leave before another one of these nerds tries to ask me another question.

Seems to be pretty much the entire point of Bad Teacher (2011).

Literature

A minor character, but still an example: Phineas Nigellus in Harry Potter and the Order of the Phoenix has a nice little rant about why he hated being a teacher, which doubles as a long overdue "The Reason You Suck" Speech to the increasingly petulant Harry.
Pretty much every teacher at James Horwitz Elementary. In the main universe anyway.

Live-Action TV

Kieran from Skins - they even try to pack him off on a motivational course ("the Feeling, Healing, Teaching Program"). He functions as a confidant and wannabe father figure for Naomi - until he misreads the signals and tries to kiss her.
- Most of the Roundview staff seem to be heading this way actually, if they're not there already.
Grantly Budgen from Waterloo Road.
Very few of the characters in Teachers seem interested in doing any actual teaching.
In an episode of My Name Is Earl, Earl decides to go back to high school so he can learn what he needs to learn to get his GED. He finds that all the teachers there are apathetic, as they have been beaten down by mean students like Earl once was.
Professor Ian Duncan on Community spends whole periods in his Intro to Anthropology class showing YouTube videos so that he doesn't have to teach. Although he's definitely apathetic, this particular example is less out of inherent apathy and more because he's actually a psychology professor who's been press-ganged into teaching an anthropology course and has no idea what he's doing; we never actually see him teach anything related to psychology, so it's possible he improves with material he's familiar with and interested in. Unlikely, but possibly.
Apparently Nick Cutter from Primeval doesn't even turn up to his own classes. When Connor tells him this, he just says "Uh-huh" and walks off.
Although he isn't technically a teacher, Shaun the probation worker from Misfits - a world-weary and visibly bored Deadpan Snarker, charged with the task of supervising a group of juvenile delinquents - fits the type precisely.
A repeated sketch in Armstrong And Miller (the Channel 4 show) was of a really Cool Teacher who was passionate, funny and well loved by his students... until the bell rang, at which point he'd become this, telling his students to "fuck off", abandoning any sort of life lesson he'd been teaching mere seconds ago, and in at least one example, directly contradicting it.
Mr Gilbert on The Inbetweeners goes between this and Sadist Teacher. He couldn't care less about his student's welfare, once noting that a pregnancy scare involving Neil was "a looming disaster for mankind but not his problem" and that the only reason anyone teaches is due to less strict background checks. This is made even better by the fact that Greg Davies, the actor who plays him, was a teacher for thirteen years.

Newspaper Comics

Mrs. Wormwood of Calvin and Hobbes. Whenever Calvin does something stupid, she thinks "Five more years 'til retirement... Five more years 'til retirement..."

Calvin: I think it's really gross the way she drinks Maalox straight from the bottle.

- Word of God has it that she believes in the value of a good education, which is why she's not happy with her job, as this idea is lost on Calvin.

Web Comics

Steve Parsons of Subnormality had a stint as one of these. Deconstructed when one of his students confronts him during a drug-induced breakdown about how he's basically fucking them all over and if he can't summon up enough energy to do his job properly he shouldn't be doing it at all.

Western Animation

Edna Krabappel has completely gone to town on this trope. She and Bart still bond a lot more than either of them would like.
- Miss Hoover, also from The Simpsons, is possibly more apathetic than Mrs. Krabappel.
- Reverend Lovejoy could also be considered one, from a "pastors are also teachers" POV.
Mr. De Martino from Daria qualifies.
Mr. Mufflin from Fanboy and Chum Chum is apathetic.
The entire faculty of Bromwell High.
Principal Lewis from American Dad.
Averted on Hey Arnold! as Mr. Simmons genuinely cares about his career, and all of his students.
Carl Moss from King of the Hill is a particularly sleazy example of an Apathetic Principal. Cuts corners wherever he can, makes no effort to running his school, and doesn't care anything about any problem that comes to his attention unless it invovles the possibility of losing his job.