Gabe Kotter (95 episodes, 1975-1979)
Julie Kotter (95 episodes, 1975-1979)
Mr. Michael Woodman (95 episodes, 1975-1979)
Juan Epstein (95 episodes, 1975-1979)
Freddie 'Boom Boom' Washington (95 episodes, 1975-1979)
Arnold Horshack (95 episodes, 1975-1979)
Vinnie Barbarino (82 episodes, 1975-1979)
Beau DeLabarre (19 episodes, 1978-1979)
Judy Borden (15 episodes, 1975-1978)
Vernajean Williams (15 episodes, 1975-1977)
Carvelli (12 episodes, 1976-1979)
Wilbur Murray (11 episodes, 1976-1979)
Angie Grabowski (7 episodes, 1978)
Mary Johnson / Mary Johnson Horshack (6 episodes, 1978-1979)
Rosalie 'Hotsy' Totsy (7 episodes, 1975-1978)
Todd Ludlow (6 episodes, 1975-1977)
Mrs. Horshack-O'Hara (4 episodes, 1977-1978)
Male Student / Student / Student in Class (1 episode, 1975-1976)
Sally (3 episodes, 1978-1979)
Mr. Jan (3 episodes, 1977-1978)
Laura Stevens (2 episodes, 1978)
Bambi Forster (3 episodes, 1975-1977)
Paula Holtzgang (2 episodes, 1977)
Cassy (2 episodes, 1977)
Mrs. Jean Tremaine (2 episodes, 1979)
Lou Grapette (2 episodes, 1977)
Nurse Bonney (2 episodes, 1978-1979)
Peter Charnoff (2 episodes, 1978)
Kelly Woodman (2 episodes, 1979)
Ms. Helms (2 episodes, 1976-1977)
Debate Team Member / Honor Student (1 episode, 1975-1976)
Uncle Harry Orshack (1 episode, 1977)
Mary Flannigan (1 episode, 1975)
Coach (2 episodes, 1975-1977)
Charlie Piper (2 episodes, 1975-1977)
Maria (1 episode, 1975)
Mr. Gore (1 episode, 1976)
Taro Takahashi (2 episodes, 1976-1977)
Ms. Wright (2 episodes, 1976-1977)
Angelo DeMora (1 episode, 1976)
Jenny Hansen (2 episodes, 1976-1977)
Miss Matusak (1 episode, 1976)
Carmen Epstein (1 episode, 1976)
Oliver Miles (2 episodes, 1976-1977)
Blonde Sweathog (1 episode, 1977)
Wally 'The Wow' Wexler (1 episode, 1977)
Dr. Mel Melmann (1 episode, 1977)
Moe Epstein (1 episode, 1977)
Mr. Lou Caruso (1 episode, 1977)
Charlie Kotter (2 episodes, 1977)
Judy Horshack (1 episode, 1977)
Mr. Hansen (1 episode, 1977)
Mr. Chicken Manager (1 episode, 1977)
Second Substitute Teacher (1 episode, 1977)
Wendy (1 episode, 1977)
Harold 'Fearless' Feldman (1 episode, 1977)
Computer (1 episode, 1978)
J. Bubba-Hampton (1 episode, 1978)
Doris (1 episode, 1978)
Sidney Braden (1 episode, 1978)
Alex Welles (1 episode, 1975)
Ms. Riley (2 episodes, 1975-1977)
Lyle Flannigan (1 episode, 1975)
Mr. Ferguson (1 episode, 1976)
Andy (1 episode, 1977)
Sexy Nurse (1 episode, 1977)
Mrs. Hansen (1 episode, 1977)
Daria 'Goldie' Dia (1 episode, 1977)
Nurse (1 episode, 1977)
Bennie Moretti (1 episode, 1977)
Mr. Overly - First Substitute Teacher (1 episode, 1977)
Maxine Biffin (1 episode, 1977)
Jerry Cronkite (1 episode, 1977)
African American Sweathog (1 episode, 1977)
Big Thug (1 episode, 1978)
Detective Lieutenant Eddie Lasky (1 episode, 1978)
Ilona Garland (1 episode, 1978)
Punk (1 episode, 1978)
Arthur (1 episode, 1978)
Olga the Stripper (1 episode, 1978)
Samson Malone (1 episode, 1979)
Mary's Uncle (1 episode, 1979)
Emily (1 episode, 1979)
Scott Phillips (1 episode, 1975)
Miss Fishbeck (1 episode, 1976)
Doris Horshack (1 episode, 1977)
Brunette Sweathog (1 episode, 1977)
Expectant Father (1 episode, 1977)
Weirdo in School Yard (1 episode, 1977)
TV Announcer (1 episode, 1977)
Boom Boom's Groupie (1 episode, 1977)
Eugene 'Blow Fish' Bigelow (1 episode, 1977)
Third Substitute Teacher (1 episode, 1977)
Rachel Kotter (twin) (1 episode, 1977)
Aunt Josephine (1 episode, 1978)
Nurse Baker (1 episode, 1978)
Bobby (1 episode, 1978)
Mr. Leonard Kripps (1 episode, 1978)
Mrs. Zugler (1 episode, 1978)
Freddie (1 episode, 1978)
Eddie Mincer (1 episode, 1978)
Mrs. Myrna Fishbein (1 episode, 1979)
Waiter (1 episode, 1979)
Detective (1 episode, 1979)
Angelina (1 episode, 1979)
Charmaine (1 episode, 1976)
Robin Kotter (twin) (1 episode, 1977)
Manny Horshack (1 episode, 1977)
Mr. Finch (1 episode, 1978)
Impatient Spanish Woman (1 episode, 1978)
The Nurse (1 episode, 1978)
Desk Sergeant (1 episode, 1978)
Baby Stevens (1 episode, 1978)
Mr. Sidney Fishbein (1 episode, 1979)
Mrs. Gladstone Trevors-Smythe (1 episode, 1979)
Marine Recruiter (1 episode, 1979)
Girl in Hallway (1 episode, 1976)
Leonard (1 episode, 1977)
Ms. Jones (1 episode, 1978)
Minister (1 episode, 1979)
Orshack's Secretary (1 episode, 1977)
Female Student / Girl in Class / Cheerleader (uncredited) (14 episodes, 1976-1977)
Silvia (uncredited) (2 episodes, 1975-1977)
Student / Student Extra (uncredited) (3 episodes, 1975-1977)
Student (uncredited) (3 episodes, 1975-1977)
Male Student (uncredited) (2 episodes, 1978)
Student (uncredited) (1 episode, 1975)
Santa Claus (uncredited) (1 episode, 1976)
Kibbutzer (uncredited) (1 episode, 1976)
Mr. Cummins - Janitor (uncredited) (1 episode, 1977)
Student (uncredited) (1 episode, 1977)
No Nose Bloomberg (uncredited) (1 episode, 1977)
Man in comedy club leaning against the wall, frowning (uncredited) (1 episode, 1978)
Ambulance Orderly (uncredited) (1 episode, 1978)