|First appearance:||November 29, 1985|
|Last appearance:||September 19, 1995|
His office is located at the end of a large hallway, just a few steps down from Calvin's locker. He has had a low profile in the strip's run.
Principal Spittle is seen as a middle-aged man who always wears a suit, is balding, and wears glasses. He may not fully enjoy his job as hinted in one strip where Calvin and Susie both yelled, "IT WAS ALL HIS FAULT, MR SPITTLE!", "THAT'S A LIE! SHE STARTED IT!", "ARE YOU GOING TO SPANK US?!" and "I'LL NEVER PASS NOTES AGAIN! DON'T SPANK US!" even crying "WAAAAAAAA I WISH WE WERE DEAD!", while a thought bubble showed him thinking "I hate this job". Moreover, his expression is one of constant boredom in the face of Calvin's antics as Miss Wormwood often sends him to the principal's office.
- Calvin imagined Principal Spittle as a Zorg in a Spaceman Spiff fantasy.
- Principal Spittle debuted in the same strip as Spaceman Spiff.
- Susie believes the hall to his office was made very big on purpose.
- In the same arc, it's revealed that Principal Spittle has "quite a file" on Calvin, indicating that Calvin has a tendency to get in trouble at school.
- His name has only been mentioned in one story line, and twice, and both times were by Susie Derkins.