Anyone who’s been on the internet or listened to Vampire Weekend has heard of the oxford comma. This small, specific punctuation mark has received outsized attention and a meme-like status, despite simply being an optional tool of written communication. Although grammarians and internet pundits alike have large opinions about the little mark, let’s get one thing out of the way: it usually doesn’t matter whether you use it or not.
There are a few key instances in which the oxford comma is necessary, but mostly, it’s fine if you opt not to use one. Nonetheless, let’s clarify a few things: What is the oxford comma, and how do you use it?
If you choose to employ the oxford comma, you’ll find it might make your writing a little more clear and stylish. Let’s explore this small, oft-spoken about piece of punctuation.
What is the Oxford Comma?
Despite its pretentious name and boisterous supporters, the oxford comma is actually a helpful tool for clarity in written communication. Simply put, an oxford comma is a comma that separates the second-to-last item in a list of three or more items, placed before the word “and” or “or” in that list.
An oxford comma is a comma that separates the second-to-last item in a list of three or more items.
Also known as a serial comma, series comma, or the just-as-pretentious “Harvard comma”, the oxford comma is usually optional, though occasionally it helps add clarity to a sentence, depending on the context of that sentence. We’ll explore those situations shortly, but first, let’s see the oxford comma as it’s typically used.
Oxford Comma Examples
The oxford comma is used in a serial list, or a list of at least three items that are divided by commas. The final item of a serial list is typically separated by a conjunction “and” or “or”, and the oxford comma precedes that conjunction.
Here’s a sentence without an oxford comma:
I am going to buy butter, milk and eggs.
And here’s an oxford comma example:
I am going to buy butter, milk, and eggs.
That comma after “milk” and before “and” is the oxford comma. As you can see, it doesn’t change the meaning or interpretation of the sentence. Here’s another set of examples, one without the optional mark:
Today, I will either write an article, practice guitar or watch TV.
And, here’s the oxford comma example:
Today, I will either write an article, practice guitar, or watch TV.
Again, the meaning of the sentence hasn’t been impacted. So it’s hardly the most important piece of punctuation in conventional English usage.
That said, there are occasions when the oxford comma does impact how a sentence is read, making it essential. More on that below.
When to Use an Oxford Comma (no ifs, ands, or buts here).
Occasionally, the context that a serial list is set in will determine the necessity of the oxford comma. It is essential to use when the writer is clarifying the existence of a serial list—otherwise, it might not look like a list to the reader.
Here’s an example sentence using the punctuation mark:
At dinner, we talked about who’s getting married, Harry Styles, and Taylor Swift.
Now, here’s what the sentence looks like without a serial comma:
At dinner, we talked about who’s getting married, Harry Styles and Taylor Swift.
Do you see the ambiguity? The latter sentence can be read as saying that Harry Styles and Taylor Swift are getting married. Let’s not agitate any fandoms if we can help it.

No one is going to misinterpret this sentence if you don’t use an oxford comma, but the image this sentence provokes is still funny.
Here’s another example in which we need the oxford comma to clarify the presence of a serial list:
I swam in the lake with my dogs, Mom and Dad.
Maybe you hate your parents, or maybe they’ve been acting doggishly. If not, then you’ll want that extra comma:
I swam in the lake with my dogs, Mom, and Dad.
Now, the oxford comma isn’t the only way to clarify a sentence. Here’s another way to write it:
I swam in the lake with Mom, Dad and my dogs.
Or, another way:
I swam in the lake with my dogs, and also with Mom and Dad.
So the oxford comma is not the only way to write a clear, grammatically correct sentence. But you can understand why it might be important in certain contexts. Otherwise, you risk the first item in your list modifying the other items, or else simply communicating something you didn’t mean.
Style Guides That Require Serial Commas
The oxford comma is optional in most contexts. However, if your work requires you to follow a specific style guide, you’ll need to incorporate it into your writing no matter the context. Those style guides that require the oxford comma include:
- Chicago
- AMA
- APA
- MLA
- CSE
- AIP
- MHRA (Britain)
It’s also a requirement for the United States Government Printing Office, and highly recommended by guides like The Elements of Style by Strunk & White.
Only the AP style guide opposes the use of the oxford comma, except in instances where it adds essential clarity (as in the specific instances above). Additionally, many newspapers and periodicals deem the oxford comma unnecessary or trivial, including The New York Times, The Economist, The Guardian, and The Times (UK).
Settling the Debate: Should I Always Use the Oxford Comma?
For most sentences, the oxford comma is inessential. Any strong feelings about the punctuation mark are heightened in the way that the internet heightens even the most trivial topics into life-or-death matters.
Nonetheless, we advise consistent use of the oxford comma, regardless of the sentence you use it in. Why? For a few reasons:
1. It’s one less thing to think about
Since there are occasional instances in which the serial comma is essential, you might as well use it all the time. Otherwise, you might have to stop and read each serial list you write to decide if it needs the comma or not, and at that point, you’re breaking up your own writing flow on a mostly trivial matter. Make it a habit. A practice that errs on the side of caution allows you to maintain the flow of writing.
2. It gives each item of a list equal weight
When you read a comma, you typically create a brief mental pause in the flow of a sentence. As such, when each item in a list is followed by a punctuation mark, each item is given that same brief pause, and it has the psychological effect of giving equal weight to words.
3. It doesn’t imply a stronger relationship between the final two items of a list
A list without the serial comma might suggest a stronger relationship between the final two items of that list. Here’s a sentence without that comma:
My list of errands includes the grocery store, the gym, the cobbler, the coffeeshop, the mall and the post office.
Without that oxford comma, the mall and the post office feel as though they’re conjoined in a way the other items of the list aren’t. They might even seem to be geographically near one another, even if they’re on opposite sides of town.
To reiterate, this is extremely trivial. It is nonetheless the type of thing we think about when we pay close scrutiny to language.
4. It is simply a more stylish, elegant way of writing
There’s something nice about a list where every item has equal weight, size, and proportion. It makes a sentence feel balanced. It’s an easy bit of punctuation to incorporate into your writing style.
Add to this the fact that an oxford comma is always clear, never misdirects the reader, and affords the reader a sense of flow as they write, and it becomes clear: why not use it?
Use, or Don’t Use, the Oxford Comma at Writers.com
Whether or not you use the oxford comma, you can explore matters of style and voice in the classes at Writers.com. Check out our upcoming writing courses, where you’re free to experiment with every aspect of language, pretentious punctuation included.
This is insightful. In the 1970s and 80s, we were taught to list items by joining the last two words with only “and” without a comma. After reading this piece, it now makes sense why Grammarly always insists on a comma before the “and in the list of items. Yes, indeed, the comma brings clarity and much better understanding when a sentence contains a list of items, and I now know that it is called an “Oxford comma.”
This is a great article on the Oxford comma. It clarifies what the Oxford comma is, how to use it, and the difference it makes in sentences. Thank you for sharing this important information, Sean.
This is an excellent article. The bottom line is to use the comma when it clarifies meaning: On the grocery list I found eggs, crackers and cheese. As I stand staring at the boxes of crackers, I wonder. Should I get a box of crackers and go to the dairy aisle for cheese? Or should I buy the single box of crackers that has a cheese product included? I can get in a lot of trouble at home if I bring the wrong thing. Are ‘crackers and cheese’ one item for a lunch box? Are we entertaining with a cheese plate with crackers? Use a comma.
Thank you for this clarifying article. I always use the Oxford comma, but now I feel more confident using it.
On the other hand, the lack of the Oxford comma cost this dairy 5 million. So they are crucial in contracts. https://www.nbcnews.com/news/us-news/think-commas-don-t-matter-omitting-one-cost-maine-dairy-n847151
Long live the Oxford comma. In addition to the instances here where it’s necessary for clarity, I like the *consistency* of using it even when it’s not. I’m a little OCD that way.
Great article!