In the SpongeBob SquarePants series, the characters celebrate fictional holidays, as well as real holidays, including:
- February 15 - Annoy Squidward Day - A day SpongeBob and Patrick annoy Squidward more than usual. ("Employee of the Month")
- June 8 - Best Friends Day - A day meant to honor best friends. ("The Gift of Gum")
- March 8 - The Bikini Bottom Annual Free Day - A day when all products are free, or as thought to be by Mr. Krabs. ("The Smoking Peanut")
- April 17 - National High Five Day - A day when Bikini Bottomites give each other high fives.
- July 5 - Work-Without-Your-Hands-Day - A day when no one in Bikini Bottom uses their hands at work. ("The Clash of Triton")
- August 15 - National No SpongeBob Day ("Gone")
- August 30 - National No Patrick Day ("Gone")
- January 25 - Opposite Day - You do the opposite of what you normally do (except breathing, living, eating, etc.). ("Opposite Day")
- November 7 - Employee Brotherhood Day - Mr. Krabs makes employees give gifts to each other. ("Dying for Pie")
- December 27 - Free Balloon Day ("Life of Crime")
- Unknown - Jellyfishing Day
- Unknown - Hula Day
- Unknown - Eat More Corn Day
- Unknown - Paint Your Shoes Day
- Unknown - Extra Thumb Day
- Unknown - Armpit Lather Day
- Unknown - Give Mr. Krabs All Your Money Day
- Unknown - Wet Noodle Sculpture Day
- Unknown - Great Pickle Race Day
- Unknown - Drive Squidward To Madness Day
- Unknown - Dope Day - A day stated by Squidward that everyone else is a dope.
- Unknown - Nope Day - A day when you say "nope" a lot.
- Unknown - National Dress As Your Boss Day
- Unknown - Down Low Day - A day where people give each other low fives.
Note: Due to religious reasons and/or the holiday being obvious, some definitions will not be present.
- New Years (briefly referenced in "Karate Island")
- Valentine's Day ("Valentine's Day" and "Breath of Fresh Squidward")
- April Fool's Day ("Fools in April")
- Easter ("Breath of Fresh Squidward")
- Fourth of July - This may mean Bikini Bottom is part of the United States of America. ("Breath of Fresh Squidward")
- Leif Erikson Day - A "holiday" to honor its namesake. Although the narrator said that SpongeBob made this day up, SpongeBob did not, as it is actually a real-life holiday that occurs every year on October 9. ("Bubble Buddy")
- Halloween ("Scaredy Pants")
- Christmas ("Christmas Who?" and "It's a SpongeBob Christmas!")
- Founders Day - as featured in What's Eating Patrick?.