Teachers have one of the hardest jobs out there, but you wouldn’t know it by watching television. Three new comedies this year portray teachers as inept, inappropriate or some unfortunate mix of both: TV Land’s “Teachers,” TruTV’s “Those Who Can’t” and “Vice Principals,” which premiered July 17 on HBO.

Comedy is the key word here, and poking fun at teachers helps the shows mine humor, to varying degrees of success. But in the grand scheme of workplace television shows, teachers get a particularly bad rap.

It wasn’t always this way, according to Mary M. Dalton, a media scholar and professor at Wake Forest University. Earlier portrayals of teachers on television, starting with the 1950s NBC sitcom “Mister Peepers,” tended to be overwhelmingly respectful of the teaching profession.

“Now, it’s like we’ve turned a corner and it’s disheartening,” says Dalton, who co-authored the 2008 book “Teacher TV: Sixty Years of Teachers on Television.”

Dalton says that in the past 15 years, public discourse about the education system has had a negative influence on teacher roles on television, inspiring some teacher characters who appear “burned out, incompetent, unfulfilled, immature, irresponsible and worse.”

Dalton says she stopped watching CBS’ “Mike and Molly” after the fourth-season premiere in 2013. Molly (Melissa McCarthy) jumps out of her fourth-grade classroom window shortly after passing out a state-mandated standardized test, effectively ending her teaching career. Her parting words to her confused students: “Don’t settle! Follow your dreams! Wherever they may take you!”

Here’s a (by no means complete) list of memorable shows featuring teachers and school administrators, ranked from the most respectful of the profession to the least.

“Boy Meets World” (1993)

As Cory Matthews and his friends navigated their way through adolescence, they met Mr. Feeny (William Daniels), a no-nonsense teacher-turned-principal who happened to be one of Cory’s neighbors, and his younger, cooler counterpart, the motorcycle-riding Jonathan Turner (Anthony Tyler Quinn). Archetypes? Maybe. But they both made lasting impressions on fans of the show and have since resurfaced in its Disney Channel spin-off “Girl Meets World,” which features Cory as a middle school teacher.

“The Wire” (2002)

The fourth season of the gritty HBO drama offers one of the more realistic pop culture depictions of teaching in cop-turned-math-teacher Roland “Prez” Pryzbylewski (Jim True-Frost). Mr. Prezbo, as many of his students call him, ends up being more adept at teaching than he is at law enforcement: He genuinely cares about his students, and his relationships with them are infused with mutual respect.

“Hangin’ With Mr. Cooper” (1992)

This TGIF sitcom was more about Mark Cooper’s (Mark Curry) relationship with his female roommates than about his role as a substitute teacher and basketball coach, but classroom scenes portrayed him as a cool and funny role model to his students — traits that translated to his rapport with his younger cousin Nicole (played by Raven-Symoné) and his young neighbor Tyler (Marquise Wilson).

“My So-Called Life” (1994)

To the dismay of its cult fan base, this teen drama was canceled by ABC after only one season, but it gave us the groundbreaking Mr. Katimski (Jeff Perry), an English teacher who happened to be gay. He was a mentor to Enrique “Rickie” Vasquez (Wilson Cruz), even taking in the gay teenager after his family kicked him out. In a 2014 interview with Cosmopolitan, Perry recalled one of Mr. Katimski’s indelible lines, delivered to Vasquez: “Nobody should hate who they are.”

“Boston Public” (2000)

David E. Kelley’s foray into the education system gets points for actually focusing on teachers and the challenges they face in the classroom. Despite mixed reviews from critics, the Fox drama won a Peabody Award in 2002 for “Chapter 37,” an episode that featured frank conversations between faculty members and students about the use of the N-word.

“Saved by the Bell” (1989)

True “Saved by the Bell” fans know that the show was conceived as a revamped version of “Good Morning, Miss Bliss,” a short-lived Disney Channel show that focused more on Miss Bliss (Hayley Mills) than on her students. Principal Belding (Dennis Haskins) was one of a few characters who appeared in both shows, and he remains a memorable fixture, even if he too often put the “pal” in principal.

“Degrassi: The Next Generation” (2001)

The long-running Toronto-set series — now airing as the Gen Z-focused “Degrassi: Next Class” on Netflix — has had its share of well-intentioned teachers and administrators, though a few have engaged in inappropriate relationships with students. The difference between “Degrassi” and, say, “Pretty Little Liars,” which prominently featured a student-teacher relationship, is that “Degrassi” tends to treat such pairings as a cautionary tale.

“Welcome Back, Kotter” (1975)

Based on a comedy routine by Gabe Kaplan, this ’70s ABC sitcom featured Kaplan as Gabe Kotter, teacher to the Sweathogs, a diverse group of high school students in need of some remedial coursework. Despite his constant joking, Kotter took his students seriously when no one else seemed to.

“Glee” (2009)

The Fox musical comedy demonstrated that you can make fun of teachers while still respecting what they do. At its heart (and its best), “Glee” was about rooting for the underdogs, and that included passionate glee club advisor Mr. Schuester (Matthew Morrison), delightfully evil (but secretly warm) gym teacher-turned-principal Sue Sylvester (Jane Lynch) and sweet, obsessive-compulsive guidance counselor Emma Pillsbury (Jayma Mays).

“Teachers” (2016)

Based on a popular Web series by improv group the Katydids, this comedy follows six grade-school teachers as they navigate recess, Picture Day and impromptu parent-teacher conferences with attractive single dads. The show’s humor relies heavily on shtick and the juxtaposition of their efforts to shape the next generation and their inappropriate conversations in the teachers lounge.

“Those Who Can’t” (2016)

Also the work of an improv troupe (Denver-based the Grawlix), “Those Who Can’t” lives up to its unfortunate title with inappropriate antics (one teacher whips up a pitcher of “virgin, barely alcoholic” margaritas for his Spanish class) and physical comedy. Does every piece of furniture have to break?

“Vice Principals” (2016)

This comedy scrapes the bottom of the barrel as Walton Goggins and “Eastbound & Down’s” Danny McBride star as two vice principals vying for the top job at their suburban high school. Nothing is off-limits here: They routinely engage in profanity-laced exchanges with students, and McBride’s character directs unsettling advances to one of his female colleagues.