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What Is the Oxford Comma? Rules and Examples
The Oxford comma is the comma before "and" or "or" at the end of a list of three or more items, as in "red, white, and blue." It's also the most argued-about comma in English. This guide explains what the Oxford comma is and when it changes the meaning of a sentence. It also covers which style guides require it and whether you should use it.
Quick answer: the Oxford comma
What it is.
The comma before the final "and" or "or" in a list of three or more: "eggs, toast, and coffee." It's also called the serial comma or the Harvard comma.
Who uses it.
APA, MLA, Chicago, and AMA use it. AP and most newspapers leave it out of simple lists.
Should you?
Follow your required style guide. If none applies, use it consistently, because it prevents more confusion than it causes.
| Without the Oxford comma | With the Oxford comma | What changes |
|---|---|---|
| I'd like to thank my parents, Ayn Rand and God. | I'd like to thank my parents, Ayn Rand, and God. | Without it, Ayn Rand and God can read as the parents. |
| We met the coaches, a former Olympian and a chef. | We met the coaches, a former Olympian, and a chef. | Without it, the coaches seem to be the Olympian and the chef. |
| The menu included soup, salad and macaroni and cheese. | The menu included soup, salad, and macaroni and cheese. | With it, "macaroni and cheese" clearly stays one dish. |
| She packed her laptop, charger and notes. | She packed her laptop, charger, and notes. | Nothing. Both are clear, so this is a style choice. |
What Is the Oxford Comma?
The Oxford comma is the comma placed after the second-to-last item in a list of three or more, right before the conjunction. In "The flag is red, white, and blue," it's the comma after "white."
It goes by three names. "Oxford comma" and "Harvard comma" come from the university presses that used it in their house styles. "Serial comma" describes what it does: it separates the last items in a series.
The Oxford comma only applies to lists of three or more. A list of two items never takes a comma before "and": "salt and pepper," not "salt, and pepper." It also applies before "or": "Do you want tea, coffee, or juice?"
Oxford Comma Examples: When Does It Change the Meaning?
Most of the time, the Oxford comma doesn't change what a sentence means. It matters in two situations. The last two items might read as a description of something earlier, or an item might already contain "and."
When the last items look like a description
A phrase that follows a noun can read as a description of that noun, called an appositive. Without the Oxford comma, a list can turn into one.
- Without: "This book is dedicated to my roommates, Priya and the dog." The roommates seem to be Priya and a dog.
- With: "This book is dedicated to my roommates, Priya, and the dog." Now there are three separate parties.
When an item already contains "and"
Items like "macaroni and cheese," "research and development," or "Johnson and Johnson" contain their own "and." The Oxford comma shows where the list item ends.
- Without: "The budget covers marketing, research and development and travel."
- With: "The budget covers marketing, research and development, and travel."
When the Oxford comma creates confusion
The Oxford comma isn't a cure-all. Occasionally it creates the ambiguity it usually prevents.
- With: "I spoke with my mother, a nurse, and a teacher." Is the mother a nurse, or are there three people?
- Fixed by rewriting: "I spoke with a nurse, a teacher, and my mother."
When neither version reads clearly, reorder the list or rewrite the sentence instead of relying on the comma.
Did a Missing Oxford Comma Really Cost a Company $5 Million?
Yes, in a sense. Maine's overtime law exempted workers involved in "canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution" of certain foods. Delivery drivers for Oakhurst Dairy argued that, without a comma after "shipment," the law exempted only packing for shipment or for distribution, not distribution itself.
In March 2017, the U.S. Court of Appeals for the First Circuit agreed the phrase was ambiguous and ruled in the drivers' favor. In 2018, Oakhurst settled the case by agreeing to pay the drivers $5 million. The case is now the standard example of a comma with legal consequences.
Not sure your punctuation is consistent?
Choose a native English proofreader who knows your style guide. Most editors offer a free sample edit of your first 300 words.
See Proofreading ServicesWhich Style Guides Require the Oxford Comma?
Academic and book publishing generally use the Oxford comma. Journalism generally doesn't. Here's where the major guides stand.
| Style guide | Oxford comma | Typically used for |
|---|---|---|
| APA | Required | Psychology, education, social sciences |
| MLA | Required | Literature, languages, humanities |
| Chicago Manual of Style | Strongly recommended | Books, history, humanities |
| AMA Manual of Style | Required | Medicine and health sciences |
| U.S. Government Publishing Office Style Manual | Required | Federal government documents |
| The Elements of Style (Strunk and White) | Required | General writing |
| New Hart's Rules (Oxford University Press) | Either style, used consistently | British publishing |
| AP Stylebook | Not used in simple lists | American journalism, public relations |
| The New York Times | Generally not used | Journalism |
| The Economist and The Guardian | Not used unless needed for clarity | British journalism |
Even guides that skip the Oxford comma allow it when a sentence would otherwise be unclear. For the other comma conventions these guides share, see our list of the 8 comma rules.
Why Is It Called the Oxford Comma?
The name comes from Oxford University Press, whose printers used the comma in their house style. Horace Hart, Printer to the University from 1883 to 1915, first issued his rules for Oxford's typesetters in 1893. They were published for sale in 1904 and became known as Hart's Rules.
The comma itself is much older than the name. The term "Oxford comma" only appeared in 1978, in Peter Sutcliffe's history of the press. "Harvard comma" comes from Harvard University Press, which follows the same practice.
Do British Writers Use the Oxford Comma?
Less often than American writers, despite the name. British newspapers such as The Guardian and The Economist leave it out of simple lists. Oxford University Press's own current guide, New Hart's Rules, allows either style as long as it's consistent. In practice, British writers tend to add it only when a list would otherwise be unclear. For more on the differences, see our guide to UK English vs. American English.
Should You Use the Oxford Comma?
Use the style your school, publisher, or employer requires. If you have a choice, the Oxford comma is the safer default for three reasons:
- It prevents most list ambiguity. It rarely causes confusion, and it often prevents it.
- It's the academic standard. APA, MLA, Chicago, and AMA all use it, so it's expected in theses, journal articles, and books.
- Consistency is easier. Using it everywhere means you never have to judge list by list.
If you write in AP style, leave it out of simple lists but add it when a list would be misread. Whatever you choose, apply it the same way throughout the document.
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Choose Your EditorFrequently Asked Questions
What is the Oxford comma?
The Oxford comma is the comma before the final "and" or "or" in a list of three or more items, as in "red, white, and blue." It's also called the serial comma or the Harvard comma. It takes its name from Oxford University Press, whose printers used it in their house style.
Is the Oxford comma correct?
Yes. Both using and omitting it are grammatically correct, so it's a matter of style. What matters is following your required style guide and staying consistent. APA, MLA, Chicago, and AMA use it, while AP style and most newspapers leave it out of simple lists.
Is the Oxford comma the same as the serial comma?
Yes. Oxford comma, serial comma, and Harvard comma all name the same mark. It's the comma before the conjunction at the end of a list of three or more. "Oxford" and "Harvard" come from the university presses that used it, and "serial" describes its job in a series.
Does APA use the Oxford comma?
Yes. APA style requires a comma before the final "and" or "or" in a series of three or more items. MLA, Chicago, and the AMA Manual of Style also use it, which makes it the norm in academic writing, including theses, dissertations, and journal articles.
Does AP style use the Oxford comma?
Not in simple lists. The AP Stylebook says to leave out the comma before the conjunction in a simple series, such as "red, white and blue." AP does allow it when a list would otherwise be unclear, for example when an item contains its own "and."
Do you use the Oxford comma with "or"?
Yes. The Oxford comma applies to lists joined by "or" just as it does to lists joined by "and": "Would you like tea, coffee, or juice?" If your style guide uses it with "and," use it with "or" too, so your lists stay consistent.
Do you use the Oxford comma in a list of two items?
No. The Oxford comma only applies to lists of three or more items. Two items joined by "and" or "or" never take a comma between them: "salt and pepper," not "salt, and pepper." A comma before "and" in a two-part sentence is a different rule, used when "and" joins two complete sentences.
Did a missing Oxford comma really cost $5 million?
Yes. In 2017, a federal appeals court ruled that a Maine overtime law was ambiguous because it lacked a comma before "or distribution." The ruling favored Oakhurst Dairy's delivery drivers. In 2018, the company settled by agreeing to pay the drivers $5 million.
Do British writers use the Oxford comma?
Less consistently than American writers. Newspapers such as The Guardian and The Economist leave it out unless it's needed for clarity. Oxford University Press's own guide, New Hart's Rules, accepts either style as long as it's used consistently throughout a document.
Can an editor make my comma style consistent?
Yes. An editor applies your chosen style, including the Oxford comma, the same way across your whole document and checks it against your style guide. At Editor World, you choose a native English editor, and most editors offer a free sample edit of your first 300 words.
Related Guides
For every other comma rule, with examples, see our 8 comma rules. For the full set of punctuation marks, read our guide to the 14 punctuation marks in English. For lists whose items already contain commas, see colon vs. semicolon.