What Is A Serial Comma? A Definitive Guide For Writers

Also known as an Oxford comma, the serial comma is a hot topic of debate in literary circles. Learn what is a serial comma in this article

A serial comma is the final comma in a list, coming before the words “‘and” or “or.” While the serial comma is no longer technically required for a sentence to be grammatically correct, many writers. In many cases, deciding whether to use the Oxford comma is a writer’s personal choice.

Some style guides require that the Oxford comma is used, while others require that the serial comma is not used. When not following a style guide, it’s up to the individual writer to decide whether using the serial comma helps their writing flow. If you want to use the latest grammar software, read our guide to using an AI grammar checker.

What Is the Oxford Comma?

What is a serial comma?
When deciding whether to use the Oxford comma, it’s essential to consider whether it’s necessary for your sentence or helps with the general flow of your writing

The idea of the Oxford comma (also known as the serial comma and the Harvard comma) is simple: it separates the final word in a list from the other words just as the preceding words were separated. Writers go back and forth on whether it’s correct to use the Oxford comma. The type of English you’re writing in can help determine whether it makes sense to use serial commas in your writing. For example, in American English, it’s often considered a requirement for proper writing to include the Oxford comma when making a list.

On the other hand, British English is a little forgiving and doesn’t necessarily require using the Harvard comma. Even in American English, it’s important to carefully check your style guide to learn whether the piece you’re writing or the publication you’re writing for requires the Oxford comma. Some publications require that writers use the comma, while others ask that they omit it (more on that shortly). Canadian English is closer to American English than British English, but writers in Canada generally avoid using the Oxford comma.

When deciding whether to use the Oxford comma, it’s essential to consider whether it’s necessary for your sentence or helps with the general flow of your writing. If you find yourself in a writing situation with no style guidelines to help you decide whether it makes sense, looking at styles of writing that you like and determining whether they use the Oxford comma can help you decide whether it’s the right fit for your writing.

How-To Use a Style Guide to Make a Decision

There is often a preferred style if you’re writing for a publication or an academic institution. You may need to read your course syllabus or look at the handbook for your institution to learn what style guidelines they follow. If you’re unable to find this information, you can also look at information put out by the institution to discover whether they prefer the use of the Oxford comma.

You’ll also want to consider the country you’re writing for when deciding whether you need to use the Oxford comma. For example, if you’re writing for a British publication in America, you must follow their preferences regarding using the Oxford comma. The same goes if you’re in Britain and writing for an American publication. If you don’t have access to international style guides, reach out to your publisher or academic institution to get the information that you need to write in the preferred style.

If you’re in America, you’ll want to consult the latest guidelines from the American Psychological Association, The Chicago Manual of Style, The MLA Style Manual, The Associated Press Stylebook, The New York Times Style Book, or the U.S. Government Printing Office Style Manual. Of course, if your organization has style guidelines, you must follow them first and foremost. If you’re in the U.K., you’ll want to follow The Oxford Style Manual or the University of Oxford Style Guide. In Canada, you’ll want to consult the stylebook developed by The Canadian Press.

Note that we did not say what each style guide currently dictates as the correct use of the Oxford comma. It’s essential to check regularly for the latest updates on stylistic guidelines, as they frequently change (like all languages). In addition, checking out the website of your preferred or required style guide can provide you with the up-to-date information you need to write correctly for your institution or publication.

Solve Ambiguity

The Oxford comma can help solve ambiguity or make a statement more ambiguous, depending on how it’s used. For example, the sentence, “Among the people interviewed by the magazine were her two ex-husbands, Jennifer Aniston and Billy Bob Thornton,” makes it sound like the person’s ex-husbands Jennifer Aniston and Billy Bob Thornton, which doesn’t make sense.

A better way to write the sentence is using the Oxford comma: “Among the people interviewed by the magazine were her two ex-husbands, Jennifer Aniston and Billy Bob Thornton.” Taking a second to add clarifying punctuation can go a long way in helping to clear confusing statements. For example, if the people listed were the ex-husbands of the person being interviewed, using the serial comma would make it difficult to figure out whether two or four people were interviewed for the story.

Examples of the Oxford Comma in Use

Any time there is a list of items, it’s possible to include the Oxford comma.

For example:

  • The colors of the rainbow are red, orange, yellow, green, blue, indigo, and violet.
  • For the cookies, we’ll need to buy flour, butter, salt, baking soda, peanut butter, chocolate chips, brown sugar, and white sugar.
  • Before the birthday party, we’ll need to pick up balloons, pizza, ice cream, soda, and the cake.

It can help to read a sentence out loud to determine whether it makes sense to use the Oxford comma. For example, if you find that you naturally pause between certain words in the sentence, a comma likely belongs in that place. On the other hand, a comma would likely not be a good fit if you read through the words quickly.

Looking for more? Check out our serial comma vs. oxford comma guide.

Should You Use the Oxford Comma?

The bottom line: it’s up to you (and the style guide you need to use) to decide whether the Oxford comma is a good fit for your writing. If you enjoy writing in a classic style, you’ll likely want to include the Harvard comma to keep your writing in line with past texts. On the other hand, if you write in a more modern style, you may find that eliminating Oxford comma use helps to modernize your work.

If you still need help, our guide to grammar and punctuation explains more.


  • Amanda has an M.S.Ed degree from the University of Pennsylvania in School and Mental Health Counseling and is a National Academy of Sports Medicine Certified Personal Trainer. She has experience writing magazine articles, newspaper articles, SEO-friendly web copy, and blog posts.