S4E1 - The Drop-Ins (1)
Gabe announces that he is now the vice-principal and Mr. Woodman is the principal. The Sweathogs are pleased, until Gabe gets strict. After Vinnie visits the school to tell the gang he's dropped out, the other Sweathogs decide to follow in his footsteps.
Nov. 25, 1978, midnight
S4E2 - The Drop-Ins (2)
With Barbarino now an ordlery at a hospital, the Sweathogs try to get jobs there, too. Meanwhile, Kotter tries to get the gang to return to school.
Sept. 18, 1978, midnight
S4E3 - Beau's Jest
Sept. 25, 1978, midnight
S4E4 - Don't Come Up and See Me Sometime
Vinnie throws the Sweathogs out of his new apartment.
Sept. 11, 1978, midnight
S4E5 - Once Upon a Ledge
Horshack saves a lonely, overlooked girl named Mary Johnson from commiting suicide by jumping off the ledge of the school.
Oct. 2, 1978, midnight
S4E6 - The Sweatmobile
The Sweathogs remember how they tried to buy a used car from Vinnie's uncle.
Sept. 11, 1978, midnight
S4E7 - Barbarino's Boo-Boo
When Mr. Woodman comes to Vinnie's hospital for an operation, Vinnie loses him and he and the other Sweathogs try to find him.
Oct. 21, 1978, midnight
S4E8 - X-Rated Education
The gang is liable to get in trouble when the x-rated film Carvelli brought into school is accidentally mixed up with a film on sexual education.
Oct. 28, 1978, midnight
S4E9 - The Barbarino Blues
Vinnie becomes depressed when it seems that he has lost his way with women.
Nov. 4, 1978, midnight
S4E10 - Washington's Clone
A younger student begins to imitate Freddie, not much to Freddie's liking.
Nov. 11, 1978, midnight
S4E11 - Frog Day Afternoon
After Horshack refuses to disect a frog in class, his grade is in jeopardy.
Oct. 9, 1978, midnight
S4E12 - A Little Fright Music
The Sweathogs opt to change Mr. Woodman's tired old school song.
Dec. 2, 1978, midnight
S4E13 - A Winter's Coat Tail
Vinnie is saddened when his new coat is stolen.
Dec. 16, 1978, midnight
S4E14 - Bride and Gloom
Juan asks Vinnie to marry his immigrant cousin.
Jan. 13, 1979, midnight
S4E15 - Barbarino's Baby
Vinnie is forced to deliver a baby in an elevator.
Feb. 3, 1979, midnight
S4E16 - The Goodbye Guy
Mr. Woodman's niece Kelly is babysitting for the Kotters when Juan drops by the apartment. The two abruptly fall in love and decide to move in together, but the romance begins to crumble when it seems that they can't respect one another's interests.
Feb. 10, 1979, midnight
S4E17 - Come Back, Little Arnold
To get up his nerve with Mary, Carvelli offers Arnold liquor. He doesn't like the idea at first, but as time goes on, he becomes addicted to drinking; developing a scary and unlikable new personality that only turns Mary away.
Feb. 24, 1979, midnight
S4E18 - The Sweat Smell of Success
Convinced that the school newspaper is too dull, Juan sets out to turn it into a tabloid, bringing down his friends' names in the process.
March 3, 1979, midnight
S4E19 - The Gang Show
Freddie and Juan plan to do an act together for the upcoming talent contest, while Carvelli has some bribed judges up his sleeves. Arnold and Beau take over as judges, leaving Murray in the third spot.
March 17, 1979, midnight
S4E20 - Oo, Oo, I Do (1)
Arnold's relationship with Mary gets serious. Then he finds out he has to move and leave the school. Upset, Arnold decides to propose marriage to Mary. She accepts.
May 25, 1979, midnight
S4E21 - Oo, Oo, I Do (2)
Arnold gets upset when the other Sweathogs tease him about not being able to provide for Mary, and he vanishes. Mary finds him and convinces him not to worry, and the two get married.
May 25, 1979, midnight
S4E22 - I'm Okay, But You're Not
Beau plays a number or pranks on Mr. Woodman.
June 1, 1979, midnight
S4E23 - The Breadwinners
While Horshack adjusts the married life, Epstein sets up an interview for a job. Washington gets the job before Epstein, unaware that it's the same job. The two get into a fight and end up in a gym ready to box.
June 8, 1979, midnight