Oxford Comma Explained: How to Use the Oxford Comma

In a sentence with a list of three or more items, the Oxford comma is the comma you place right before the coordinating conjunction and last item in the list. It is also known as a serial comma, a series comma, or a Harvard comma.

The Oxford comma is considered optional by American English language grammarians. Some specific style guides prescribe the Oxford comma at the end of a list. One such style guide comes from Oxford University Press, which accounts for the origin of the term "Oxford comma." Other style manuals, such as The AP Style Guide, advise against its use. In less formal contexts, the use of the Oxford comma has prompted heated debate based on the subjective opinions of individual writers.

The Oxford comma is easy to put into practice.

1. 1. “The ice cream flavors were vanilla, chocolate, and strawberry.” In this sentence, the comma that comes after “chocolate” and before the final conjunction, “and,” is an Oxford comma.
2. 2. "I’d listen to Steely Dan, Oingo Boingo, or Vampire Weekend." In this sentence, the comma after "Oingo Boingo" is an Oxford comma.
3. 3. “I walked through the park, picked up some groceries, and made dinner.” In this sentence, the comma after “picked up some groceries” is an Oxford comma.

Using the Oxford comma can help clarify the meaning of a sentence. Consider how the omission of an Oxford comma led to a 2014 lawsuit involving the company Oakhurst Dairy in Maine. Oakhurst Dairy issued an edict stating that "canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution" were exempt from overtime pay. This list appeared in the middle of a sentence. In this sentence, it is unclear whether the final item is “packing for shipment or distribution” as a single job or “packing for shipment” and “distribution” as two distinct jobs. Adding the Oxford comma before “or distribution” would have made it clear that distribution was its own activity not eligible for overtime pay.

Different publications have their own policies on the use of the Oxford comma.

• Style guides that encourage the use of the Oxford comma: Strunk and White's The Elements of Style, the MLA Style Manual, The Chicago Manual of Style, APA style, and the U.S. Government Printing Office Style Manual all adopt the Oxford comma in their house style. Oxford University Press and Harvard University Press famously encourage the serial comma, and it is from these style guides that the terms "Oxford comma" and "Harvard comma" evolved.
• Style guides that discourage the use of the Oxford comma: The New York Times Stylebook, the Associated Press Stylebook (or AP Stylebook), The Economist Style Guide, and The Canadian Press Style Guide advise against the use of Oxford commas. Ironically, the University of Oxford Style Guide also discourages the use of the Oxford comma.

Become a better writer with the MasterClass Annual Membership. Gain access to exclusive video lessons taught by the world’s best, including Billy Collins, Joy Harjo, Neil Gaiman, Walter Mosley, Margaret Atwood, Joyce Carol Oates, Dan Brown, and more.