The Oxford comma, also known as the serial comma, is one of the most debated punctuation marks in English. It’s the comma placed before the final conjunction (usually and or or) in a list of three or more items.
Some style guides insist on using it. Others leave it out. But here’s the real reason it matters: the Oxford comma can prevent confusion and misinterpretation in your writing.
In this article, you’ll learn what the Oxford comma is, when to use it, and how it can change the meaning of a sentence. We’ll also look at examples, style guide rules, and the famous cases where one small comma made a big difference.
What Is the Oxford Comma?
The Oxford comma (or serial comma) is the final comma in a list of three or more items, placed before the coordinating conjunction and or or.
Example with Oxford Comma:
- I packed sandwiches, fruit, and water.
Without Oxford Comma:
- I packed sandwiches, fruit and water.
In both cases, the sentence is grammatically correct. The difference lies in clarity. With the Oxford comma, each item in the list stands alone. Without it, readers might misinterpret the last two items as a combined idea.
The term “Oxford comma” comes from its early use in Oxford University Press publications. Today, it’s widely used in academic, formal, and technical writing, especially where precision matters.
Why It Matters
The Oxford comma isn’t just a style preference—it often helps prevent ambiguity.
Example 1:
Without Oxford comma:
We invited the dancers, Elvis and Tina.
➡ This could mean that Elvis and Tina are the dancers.
With Oxford comma:
We invited the dancers, Elvis, and Tina.
✔ Now it’s clear that Elvis and Tina are separate from the dancers.
Example 2 (Real-World Impact):
In 2014, a legal case in Maine involved truck drivers suing for overtime pay. The law listed tasks without an Oxford comma, leading to confusion over whether the final two items were meant to be grouped.
Original wording (without Oxford comma):
“…packing for shipment or distribution of perishable foods.”
This cost the employer $5 million because the court ruled in favor of the drivers—there was no clear separation between “shipment” and “distribution.”
Example 3:
Without Oxford comma:
I love my parents, Lady Gaga and Shakespeare.
➡ Sounds like your parents are Lady Gaga and Shakespeare.
With Oxford comma:
I love my parents, Lady Gaga, and Shakespeare.
✔ No confusion—three separate groups.
Style Guide Positions
Different style guides take different stances on the Oxford comma. Whether you use it often depends on the context and audience you’re writing for.
Chicago Manual of Style
Requires the Oxford comma. Used widely in academic, nonfiction, and book publishing.
MLA and APA Style
Recommend or require the Oxford comma. Common in student papers, research writing, and scholarly publications.
The Oxford University Press
As the name suggests, they have always supported the Oxford comma in formal and technical documents.
AP Style (Associated Press)
Omits the Oxford comma except when it helps avoid confusion. This is typical in journalism and news writing.
Tip: If you’re not following a specific guide, choose one approach and stay consistent.
Examples With and Without the Oxford Comma
Let’s look at how sentence meaning can shift depending on whether the Oxford comma is used.
Ambiguous Without Oxford Comma
- Without: She dedicated the book to her parents, Jane and God.
➡ Suggests her parents are Jane and God. - With: She dedicated the book to her parents, Jane, and God.
✔ Clear separation between all three recipients.
Clarity in Lists
- Without: For breakfast, I had toast, eggs and orange juice.
➡ Could imply the eggs and orange juice are combined. - With: For breakfast, I had toast, eggs, and orange juice.
✔ Each item stands alone.
Academic or Formal Context
- Without: The study included data from Europe, Asia and Africa.
- With: The study included data from Europe, Asia, and Africa.
✔ The Oxford comma maintains parallel structure and consistency.
When to Use It for Clarity (Even in AP Style)
Even if you follow AP Style, which typically omits the Oxford comma, there are times when leaving it out creates confusion. In these cases, AP allows or even recommends its use.
Example 1:
- Without Oxford comma: The award goes to Sam, a historian and author.
➡ Is Sam both a historian and author? Or are they three people? - With Oxford comma: The award goes to Sam, a historian, and author.
✔ Now it’s clear: three recipients.
Example 2:
- Without: The tour included stops in Paris, Rome and Naples.
➡ Sounds fine—no confusion. - With: The tour included stops in Paris, Rome, and Naples.
✔ Adds rhythm and consistency, especially in longer lists.
In short: use the Oxford comma whenever it improves clarity, even if your chosen style normally omits it.
Common Misconceptions & Counterarguments
The Oxford comma has its critics, and some writers prefer to leave it out. Let’s look at a few common objections—and the reasons many still choose to use it.
It’s Redundant
Some argue that and already separates the final item, so the extra comma is unnecessary.
🔁 But when clarity is the goal, a small redundancy is better than confusion.
It Wastes Space
In print journalism, space used to be limited, and saving characters mattered.
🔁 That’s less of an issue in modern writing, especially online or academic contexts.
No One Really Gets Confused
Not true. There are real examples (like the Maine overtime case) where millions were at stake because of a missing Oxford comma.
It’s Optional, So I Can Skip It
Technically true—but inconsistent usage weakens writing. If your style guide allows choice, pick one approach and stick with it.
Tips for Consistent Use
If you’re unsure when or how to use the Oxford comma, these tips can help you decide and stay consistent.
Follow a Style Guide
Stick with a recognized style guide (like Chicago, APA, or AP) based on the context you’re writing for—academic, journalistic, business, or general use.
Use It When Clarity Might Be at Risk
Even if your style omits it, include the Oxford comma if its absence could change the meaning of the sentence.
Avoid Switching Back and Forth
Choose a consistent rule for your writing. Flipping between using and omitting the comma can confuse the reader and weaken your style.
Know Your Audience
If you’re writing for formal, academic, or international readers, it’s safer to include it. If you’re writing for media or casual web content, you may omit it—unless clarity demands it.
Frequently Asked Questions
What is the Oxford comma?
The Oxford comma (also called the serial comma) is the final comma used before the word and or or in a list of three or more items. Example: apples, bananas, and grapes.
Is the Oxford comma grammatically correct?
Yes. It’s grammatically correct and widely accepted in formal writing. Whether or not you use it depends on the style guide or context.
Should I use the Oxford comma in academic writing?
Most academic styles—like APA, MLA, and Chicago—recommend or require the Oxford comma to avoid ambiguity.
Does the AP Stylebook ban the Oxford comma?
Not exactly. AP Style advises against using it unless needed for clarity. So, even in journalism, the Oxford comma is allowed when a sentence could otherwise be misread.
Can leaving out the Oxford comma change the meaning of a sentence?
Yes. Omitting it can sometimes cause confusion or unintended groupings in lists. Including it often ensures clarity.