What Is The Oxford Comma And Why Is It So Important?

What Is The Oxford Comma

What is an Oxford comma, and what is all the fuss about?

We call it the Oxford comma because printers, readers, and editors at Oxford University Press used it. It is the publishing arm of the University of Oxford.

In brief, also known as the Serial Comma or Harvard Comma in American English, it is a comma inserted before the last item in a list that is preceded by the word and, and sometimes the word or.

You shouldn’t confuse it with a regular comma, which we use with a coordinating conjunction such as but, for or so, for example.

The Oxford Comma debate

The debate about whether to use the Oxford comma or not has raged for years.

But it got a lot of attention due to a court case in the US.

The state law case revolved around one clause that defined when overtime pay was to be paid to truck drivers by Oakhurst Dairy.

The canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution of:

(1) Agricultural produce;
(2) Meat and fish products; and
(3) Perishable foods.

The legal issue was the last part of the introductory phrase following the last comma.

With the lack of a comma before “distribution,” the clause could be interpreted to mean that the truck drivers, who had no part in “packing for shipment or distribution,” should be paid because their job was “distribution” and not “packing for shipment or distribution.”

Anyway, the truck drivers won their case.

And with it came the renewed interest in the use of this small piece of punctuation – the comma.

Probably because it was about money, which made it more newsworthy.


It’s only a comma. I just add one when it feels right

comma rules

No other punctuation mark causes as much trouble as the comma.

Adding a comma is not about feeling right or when you think you would typically pause for breath or emphasis in a spoken sentence.

The use of the comma rules is quite, well, at least, reasonably clear according to the Oxford University Press Style Guide.

1. Use a pair of commas to surround a non-defining clause.

2. Do not use commas to surround a defining clause.

3. Use commas to surround a non-defining word or phrase.

4. Do not use a comma where defining information is used at the start of a sentence.

5. Do not use a comma to join two main clauses, or those linked by adverbs 
or adverbial phrases.

6. Use a comma after an introductory adverb, adverbial phrase, or subordinate clause. Or use a pair of commas surrounding it if it is in the middle of a sentence.

7. Do not use a comma after a time-based adverbial phrase.

8. Use a comma between multiple qualitative adjectives (those which can be used in the comparative/superlative or modified with ‘very,’ ‘quite,’ etc.).

9. Do not use a comma between multiple classifying adjectives: absolutes which either are or are not, such as ‘unique,’ ‘English,’ ‘black,’ etc. (although note that stylistically these can be modified).

10. Use a comma between items in a list. Note that there is no comma between the penultimate item in a list and ‘and’/‘or’ unless required to prevent ambiguity – this is sometimes referred to as the ‘Oxford comma.’ However, always insert a comma in this position if it would help prevent confusion.


Comma confusion?


In fact, this special comma is very easy to use when compared to all the other comma rules.

I can manage rule number 10 because it is not confusing at all. But I have to admit that I sometimes cheat and use a grammar checker to help me with rules one to nine.

One classic example of when the comma makes a difference is in this famous (or perhaps infamous) book attribution.

To my parents, Ayn Rand and God.

You could easily understand that the author’s mother is Ayn Rand, and her father is God. But one comma prevents ambiguity.

To my parents, Ayn Rand, and God.

Generally, though, it’s very often about commas in a list.

If the last item in a list has “and” before it and doesn’t associate with the item before “and,” the comma avoids any confusion.

So, which do you prefer? Would you like your green beans served with or without ice cream?

My menu for my dinner guests tonight will be beef stew, new potatoes, green beans and ice cream.

My menu for my dinner guests tonight will be beef stew, new potatoes, green beans, and ice cream.

I have to tell you that my father was not at all talented at hypnosis and was a ravenous meat eater.

In the first sentence, it is clearly the opposite meaning. One small comma corrects the ambiguity in the list.

It surprised me to find myself alone with my father, a hypnotist and a vegetarian.

It surprised me to find myself alone with my father, a hypnotist, and a vegetarian.


But not everyone agrees with this Oxford style comma

writing style

Let’s look at what some well-known English language style guides recommend regarding the Oxford comma.

In fact, the Oxford comma is always a matter of style.

english language style guides

The Chicago Manual of Style, 16th edition (University of Chicago Press, 2010), paragraph 6.18

“When a conjunction joins the last two elements in a series of three or more, a comma … should appear before the conjunction. Chicago strongly recommends this widely practiced (sic) usage.”

The Times Style Manual

“Avoid the so-called Oxford comma; say ‘he ate bread, butter and jam’ rather than ‘he ate bread, butter, and jam.'”

The New York Times Stylebook

“In general, do not use a comma before and or or in a series.”

The Australian Government Publishing Service‘s Style Manual for Authors, Editors and Printers

“A comma is used before andor, or etc. in a list when its omission might either give rise to ambiguity or cause the last word or phrase to be construed with a preposition in the preceding phrase. … Generally, however, a comma is not used before andor, etc. in a list.”


BuzzFeed uses the serial (aka Oxford) comma: e.g., We picked up cyan, magenta, yellow, and black balloons for the party.

Cambridge University Style Guide

An Oxford comma is the final comma used before an “and” at the end of a list and is used to avoid ambiguity:

The family meal was soup, fish and chips, and ice cream.

The jumper is available in green, yellow, and black and white.

Associated Press Style Guide (AP Style)

The Serial Comma/Oxford Commas

The serial comma is a comma that appears before “and” in a list. Omit the serial comma unless the sentence would be unclear without it.

I think that makes four guides that are for the comma and three against it. So it is a close vote.


Which comma rule should you use?

Due to the different stances the style guides above take, it is up to you to decide.

But it is more about style than strict grammar rules.

However, when you are not sure, or if you think your readers will be in doubt, use the extra comma.

You don’t have to obey rules but rather look at its use as a tool to improve the clarity of your writing.

And yes, I am definitely an Oxford comma proponent. What about you?


Related reading: Use The Comma Before And In A List Avoids Misunderstandings

7 thoughts on “What Is The Oxford Comma And Why Is It So Important?”

  1. “To my parents, Ayn Rand and God”
    “To my mother, Ayn Rand, and God”
    That on its own proves that slavish devotion to either rule can create confusion. Anyone saying “you must” or “you mustn’t” should be shunned and ignored. Use your intelligence and choose.

    But for the sake of argument, consider:
    “Eggs and bacon”
    “Sausage, eggs and bacon”
    What has changed about the relationship between “eggs and bacon” that requires a comma, where none was needed before?

  2. I use it 100% of the time. None of the arguments against it hold water, in my estimation. For the sake of parallelism, for the sake of consistency, for the sake of clarity, each item but the last in a list should be followed by a comma. The appearance of “and” or “or” shouldn’t really matter. “I like pork, beef, chicken.” “I like pork, beef, and chicken.” Other articles have pointed out that if the items in a list are separated by semicolons instead, the last one is NOT optional… “I gave awards to Jack and Jill; Mother Goose and Father Time; and the Three Billy Goats Gruff.” In the days of printing with blocks, eliminating the comma to save precious seconds and precious space made sense, but now with everything printed electronically, there’s no reason to skip the Oxford comma.

  3. I advocate using the Oxford comma as a complete rule. This avoids the ‘eats shoots and leaves’ error. Also, it enables the absence of the comma to be an indication that the words where it doesn’t appear are grouped. Without it, what seems perfectly clear to you may still confuse another person.
    ‘We bought fruit drinks, and bananas, and fish and chips, and peaches and cream, cakes, and scones’ (Or ‘peaches, and cream cakes’.)
    We bought fruit, drinks, and bananas, and fish, and chips, and peaches, and cream, cakes, and scones
    We bought fruit drinks and bananas and fish and chips and peaches and cream cakes and scones

  4. Very enlightening. Thank you.
    Question for you: why didn’t you use “my” before dog? Just curious.

    1. Hi Cynthia.

      I could have used “my” again before “dog” and without a comma.

      In a simple list, you would only use “my” once. “I like my house, car and computer.

      But in a list where it is more complex, or unclear, the comma helps avoid the repetition of “my”.

  5. I’m a ‘use it if the sentence would otherwise be confusing’ person, but if it is perfectly clear without it, I omit it.

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