September 1st
- Be Kind Day
- Building and Coding Staff Appreciation Day
- Calendar Adjustment Day
- Cherry Popover Day
- Chicken Boy’s Day
- Day of Awareness for the Dolphins of Taji (International)
- Emma M. Nutt Day
- No Rhyme nor Reason Day
- Random Acts of Kindness Day
- Save Japan’s Dolphin’s Day
- Toy Tips Executive Toy Test Day
September 2nd
- Bison Ten Yell Day
- Coconut Day
- Great Bathtub Race
- Labor Day ~ First Monday of September
- Mouthguard Day
- No Patrick Day
- VJ Day
September 3rd
- Another Look Unlimited Day ~ Day after Labor Day
- Bowling League Day
- Day of Prayer for Victims of Hurrican Harvey
- Skyscraper Day
September 4th
- Newspaper Carrier Day
September 5th
- Be Late for Something Day
- Cheese Pizza Day
- Day of Charity (International)
- Jury Rights Day
September 6th
- Bring Your Manners to Work Day ~ First Friday of September
- Dog Walker Appreciation Day ~ First Friday of September
- Fight Procrastination Day
- Food Bank Day ~ First Friday of September
- Lazy Mom’s Day ~ First Friday of September
- Read a Book Day
- Stand Up to Cancer Day ~ First Friday of September
September 7th
- AKC Responsible Dog Ownership Day
- Attention Deficit Disorder Awareness Day
- Beard Day (World) ~ First Saturday of September
- Google Commemoration (Founded)
- Grandma Moses Day
- Grateful Patient Day
- Neither Rain Nor Snow Day
- Salami Day
- Tailgating Day ~ First Saturday of September
- Writing Date Day ~ First Saturday of September
September 8th
- Ampersand Day
- Date Nut Bread Day
- Grandparents Day ~ First Sunday after Labor Day
- Hug Your Hound Day ~ Second Sunday of September
- Literacy Day (International)
- Pardon Day
- Pediatric Hematology/Oncology Nurses Day
- Pet Memorial Day ~ Second Sunday of September
- Pet Rock Day
- Physical Therapy Day (World)
- Virgin Mary Day
September 9th
- Bluebird of Happiness Day
- Boss/Employee Exchange Day ~ First Monday after Labor Day
- Buy a Priest a Beer Day
- Care Bears Share Your Care Day
- Fetal Alcohol Spectrum Disorders Day
- Teddy Bear Day
- Opposite Day
- Wonderful Weirdos Day
September 10th
- Ants on a Log Day ~ Second Tuesday of September
- Sewing Machine Day
- Suicide Prevention Day (World)
- Swap Ideas Day
September 11th
- 911 Remembrance Day
- Day of Service and Remembrance
- Libraries Remember Day
- Make Your Bed Day
- No News is Good News Day
- Patriot Day
September 12th
- Chocolate Milk Shake Day
- Day for South-South Cooperation
- Day of Encouragement
- Police Woman’s Day
- Report Medicare Fraud Day
- Video Game Day
September 13th
- 9X13 Day
- Blame Someone Else Day ~ First Friday the 13th of the Year
- Celiac Awareness Day
- Chinese Moon Festival ~ Date Varies
- Chocolate Day (International)
- Defy Superstition Day
- Fortune Cookie Day
- Friday the 13th
- Hug Your Boss Day ~ Date Varies
- Kids Take Over the Kitchen Day
- Peanut Day
- Positive Thinking Day
- Programmer’s Day ~ the 256th day of the year, on leap year it is on 9/12
- Roald Dahl Day
- Scooby-Doo Day
- Uncle Sam Day
September 14th
- Banana Day ~ Second Saturday of September
- Crab Fest Day (International)
- Cream Filled Doughnut Day
- Day of Remembrance for Aborted Children ~ Second Saturday of September
- Drive Your Studebaker Day (International) ~ Second Saturday of September
- Farmer’s Consumer Awareness Day ~ Second Saturday of September
- Hollerin’ Day ~ Second Saturday of September
- Iguana Awareness Day
- Kreme Filled Donut Day
- Live Creative Day
- Prairie Day ~ Second Saturday of September
September 15th
- 8-Track Tape Day
- Cheese Toast Day
- Cheeseburger Day
- Day of Democracy
- Dot Day (International)
- Felt Hat Day
- Google.com Day
- Greenpeace Day
- LGBT Center Awareness Day
- Make a Hat Day
- Online Learning Day
- Tackle Kids Cancer Day
- Wife Appreciation Day ~ Third Sunday of September
- Women’s Friendship Day ~ Third Sunday of September
September 16th
- American Legion Day
- Ann Dudley Bradstreet Day
- Collect Rocks Day
- Guacamole Day
- Mayflower Day
- Mexican Independence Day
- Play-Doh Day
- Preservation of the Ozone Layer Day (International)
- Respect for the Aged Day ~ Third Monday of September
- Stay Away from Seattle Day
- Step Family Day
- Tattoo Story Day
- Trail of Tears Commemoration Day
- Working Parents Day
September 17th
- Citizenship Day
- Constitution Day
- Country Music Day (International) ~ Third Tuesday of September
- Get Ready Day
- IT Professionals Day ~ Third Tuesday of September
- Monte Cristo Day
- Time’s Up Day
- VFW Ladies Auxiliary Day
September 18th
- Air Force BirthdayApple Dumpling Day
- Ceiling Fan Day
- Cheeseburger Day
- Chiropractic Founders Day
- Day Against DRM
- HIV/AIDS and Aging Awareness Day
- Hug a Greeting Card Writer Day
- Rehabilitation Day ~ Third Wednesday of September
- Respect Day
- School Backpack Awareness Day ~ Third Wednesday of September
- Water Monitoring Day (World)
September 19th
- Butterscotch Pudding Day
- Talk Like a Pirate Day
- Teach Ag Day ~ Third Thursday of September
September 20th
- Clean Up the World Weekend ~ Third Weekend of September
- Concussion Awareness Day
- Constitution Day ~ Third Friday of September
- Doodle Day
- Grenache Day ~ Third Friday of September
- Pepperoni Pizza Day
- Pledge Across America ~ Third Friday of September
- POW/MIA Recognition Day ~ Third Friday of September
- Punch Day
- String Cheese Day
- Tradesmen Day ~ Third Friday of September
September 21st
- Alzheimer’s Day (World)
- Big Whopper Liar Day ~ Third Saturday of September
- Boys’ and Girls’ Club Day for Kids ~ Third Saturday of September
- Coastal Cleanup Day (International) ~ Third Saturday of September
- Clean Up Day ~ Third Saturday of September
- Day of Peace (International)
- Eat an Apple Day ~ Third Saturday of September
- Gratitude Day (World)
- Gymnastics Day ~ Third Saturday of September
- Locate an Old Friend Day ~ Third Saturday of September
- Miniature Gold Day
- Oktoberfest Begins (Germany) ~ Date Varies
- Peace Day (International)
- Puppy Mill Awareness Day ~ Third Saturday of September
- Red Panda Bear Day (International) ~ Third Sunday of September
- Seatcheck Saturday ~ Third Saturday of September
- Surgical Technologists Day
September 22nd
- Business Women’s Day
- Car Free Day
- Centenarian’s Day
- Chainmail Day
- Dear Diary Day
- Elephant Appreciation Day
- Great Gorilla Run Day
- Hobbit Day
- Ice Cream Cone Day
- Leg Wear Day
- Radiant Peace Day (International)
- Remote Employee Appreciation Day
- Rock n’ Roll Dog Day
- White Chocolate Day
September 23rd
- Autumn (Fall) Equinox ~ Date Varies
- Celebrate Bisexuality Day
- Checkers Day
- Dogs in Politics Day
- Great American Pot Pie Day
- Family Day ~ Fourth Monday of September
- Mabon ~ Date Varies
- Restless Legs Awareness Day
- Sign Language Day
- Snack Stick Day
- Teal Talk Day
September 24th
- Cherries Jubilee Day
- Familial Hypercholesterolemia Day
- Innergize Day (Day after Fall Equinox)~ Date Varies
- Punctuation Day
- Schwenkfelder Thanksgiving
- Voter Registration Day ~ Fourth Tuesday of September
- Woman Road Warrior Day ~ Fourth Tuesday of September
September 25th
- Ataxia Awareness Day
- Banned Websites Awareness Day ~ Last Wednesday of September
- Comic Book Day
- Math Story Telling Day
- One Hit Wonder Day
- Pharmacists Day (World)
- Psychotherapy Day
- Research Administrators Day
- Tune-Up Day
- Women’s Health & Fitness Day ~ Last Wednesday of September
September 26th
- Compliance Officer Day
- Contraception Day
- Dumpling Day
- Forget-Me-Not Day
- Johnny Appleseed Day
- Maritime Day ~ Last Thursday of September
- Remember Me Thursday ~ Last Thursday of September
- Shamu the Whale Day
- Situational Awareness Day
September 27th
- Ancestor Appreciation Day
- Brave Day ~ Fourth Friday of September
- Crush a Can Day
- Gay Men’s HIV/AIDS Awareness Day
- Google’s Birthday
- Hug a Vegetarian Day ~ Last Friday of September
- Love Note Day ~ Fourth Friday of September
- Native American Day ~ Fourth Friday of September
- Save the Koala Day ~ Last Friday of September
- Support Purple for Platelets Day ~ Last Friday of September
- Tourism Day (World)
- Vegan Baking Day ~ Last Friday of September
September 28th
- Ask a Stupid Question Day
- Batman Day
- Bright Pink Lipstick Day ~ Fourth Saturday of September
- Drink Beer Day
- Family Health and Fitness Day USA ~ Last Saturday of September
- Fish Amnesty Day ~ Fourth Saturday of September
- Fish Tank Floor Show Night
- Ghost Hunting Day ~ Last Saturday of September
- Good Neighbor Day
- Hunting and Fishing Day ~ Fourth Saturday of September
- Kids Day ~ Fourth Saturday of September
- Lace Day (International) ~ Last Saturday of September
- Museum Day ~ Fourth Saturday of September
- Nickelodeon’s Worldwide Day of Play ~ Last Saturday of September
- Public Lands Day ~ Fourth Saturday of September
- Rabies Day (World)
- R.E.A.D. in America Day ~ Fourth Saturday of September
- Rabbit Day (International) ~ Fourth Saturday of September
- Right to Know Day
- Save Your Photos Day ~ Fourth Saturday of September
- Singles Day ~ Fourth Saturday of September
- Universal Access to Information Day (International)
September 29th
- Attend Your Grandchild’s Birth Day
- Biscotti Day
- Coffee Day (International)
- Confucius Day
- Day of the Deaf (International) ~ Last Sunday of September
- Gold Star Mother’s Day ~ Last Sunday of September
- Heart Day (World)
- MAGS Day
- Michaelmas
- Mutation Day ( TMNT – Teenage Mutant Ninja Turtles)
- Rosh Hashana (starts at Sundown) ~ Date Varies
- VFW Day
September 30th
- Ask a Stupid Question Day ~ Last School Day of the Month
- Blasphemy Day
- Love People Day
- Mud Pack Day
- Mulled Cider Day
- Translation Day (International)
September
September Weekly Holidays
September Monthly Holidays