There are many puns online where not having the Oxford comma (Serial comma) can be interpreted as something other than intended, such as the infamous Sky News notification:

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It’s hilarious, I know, but on a more serious note, does the optional serial comma have any effect on readability? Being a Swede, we don’t have that optional rule at all and your Swedish teacher would make you aware of the error and make you correct it. However, when I first found out about it, I thought it increases the readability and leaves out alternative interpretations.

I often find myself stuck with terrible lists, such as a global navigation. You may have Home, Products, Solutions, Services and Support and About Us. Now, do I mean

HomeProductsSolutionsServices and SupportAbout Us


HomeProductsSolutionsServices and Support and About Us

It’s obvious to us what I mean since About Us is a top navigation item of its own, but how about nonprofessionals who are not familiar with the standard patterns of a global navigation? Could they misinterpret what I really mean leaving the optional serial comma out of the question? Does the Oxford Comma increase readability?

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    I don't consider the "Oxford Comma" as optional (certainly it wasn't optional back when I was at school). Is it an American thing to drop this comma?
    – Franchesca
    Commented Aug 22, 2014 at 8:15
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    youtu.be/8Gv0H-vPoDc?t=1m45s :-) Commented Aug 22, 2014 at 11:16
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    @David: I wonder what proportion of questions on the site could reasonably be answered, "if it made much difference, you wouldn't even be considering two different ways to do it, everyone would already be doing the one that was significantly better. Just pick either of them and get on with your life." ;-) Commented Aug 22, 2014 at 13:51
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    – TRiG
    Commented Aug 22, 2014 at 14:01
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    @SteveJessop - it's not that simple. There are cases where use of either is objectively wrong. Consider : To my parents, Jane Doe and Zeus versus To my parents, Jane Doe, and Zeus - here the Oxford comma has eliminated ambiguity. Alternatively, To my mother, Jane Doe, and Zeus is ambiguious and removing the Oxford Comma clears up the ambiguity : To my mother, Jane Doe and Zeus. Most cases can be rephrased in other ways, of course, so sticking to one form or the other means being aware that it imposes some restrictions on the phrasing you use.
    – J...
    Commented Aug 22, 2014 at 14:15

10 Answers 10


I think the top-voted answer is only partially correct... The Oxford comma can resolve ambiguity OR create ambiguity, depending on context. This is the reason that grammar experts and style guides disagree on the use of the Oxford comma - sometimes the Oxford comma helps, sometimes it actually hurts readability. Consider the following examples...

"I gave gifts to my parents, Jim and Beth." In this example, the lack of the Oxford comma creates a serious problem! Is "Jim and Beth" an appositive describing my parents, in which case I've given gifts to only two people? Or is this a list of three independent items? There's no way to know. The Oxford comma clears it up, though... "I gave gifts to my parents, Jim, and Beth." Now all is clear! It's a list of three independent items!

Unfortunately, this can just as easily go the other way! Consider the following... "I gave gifts to my father, Jim, and Beth." In this case, the presence of the Oxford comma creates serious ambiguity. Is "Jim" an appositive describing my father, in which case I've given gifts to two people? Or is this a list of three different people, and Jim is not my father? With the Oxford comma there, we can't figure it out. But take away the Oxford comma, and it becomes very clear. "I gave gifts to my father, Jim and Beth." Ah! Now we know that three people were involved!

The Oxford comma does not universally increase or decrease readability. In some cases it helps, in others it hurts. The best practice is to consult the style guide for whatever you are writing for, follow its rules with respect to the Oxford comma consistently, and avoid crafting sentences where the Oxford comma or the lack thereof introduces a problem.

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    Why would you structure the sentence to add classifiers to part of a list but not other parts? If you only mean two people when you say "my father, Jim, and Beth", then it should be phrased as "my father, Jim, and my mother, Beth", "my father and mother", or "Jim and Beth". Or in the case that Beth is someone with no possible classifier: "my father and Beth".
    – Brian
    Commented Aug 25, 2014 at 20:59
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    For "I gave gifts to my father, Jim, and Beth", I always reduce the ambiguity by repeating the preposition: "I gave gifts to my father, to Jim, and to Beth" vs "I gave gifts to my father, Jim, and to Beth".
    – hairboat
    Commented Aug 26, 2014 at 20:31
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    I would have gone "to my parents and to Jim and Beth". But I guess this isn't english.stackexchange.com. Commented Aug 27, 2014 at 0:49
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    I absolutely agree with all the above... hence my advice to avoid crafting sentences where the Oxford comma introduces ambiguity. Ultimately, all the rules of language and grammar are arbitrary. The task of a writer is to figure out how to use those arbitrary rules to communicate clearly and effectively. Commented Aug 27, 2014 at 13:02
  • Your argument is soft. How many sentences does it help, and how many does it hurt? Commented Aug 28, 2014 at 23:00

Yes. The Oxford Comma increases readability.

When items are logically separate, putting a delimiter between them makes their separation visually obvious. Without the delimiter, the separation can still be determined, but it is not obvious.

The Oxford comma removes the requirement that the reader figure out whether item n and item n-1 are logically separate.


I agree with this answer.

I want to clarify that I gave my original answer in the context of a list of items which are definitely separate, such as in the example in the original question. In such a case, I maintain that the Oxford comma does indeed increase readability.

However, many users have very helpfully pointed out that it's possible to construct a list wherein the Oxford comma may not help (and may even hinder) readability. Many of these are cases where the distinction is made by inflection when spoken, but that's of no use in text.

Here's my addendum:

If you find yourself in a situation where the addition or removal of the Oxford comma does not unambiguously improve readability, restructure the whole sentence.

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    @DavidRicherby I know people that would disagree - my parents, Jill and John. I know people that would disagree - my parents, Jill, and John.
    – OJFord
    Commented Aug 22, 2014 at 20:52
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    @OllieFord Jill, John(,) and your parents actually agree. Your siblings -- Bob and Sue -- agree too. Fred and Jill, your cousins, are also happy. If you're relying on commas to resolve ambiguity, you should probably rephrase the sentence, anyway. Commented Aug 22, 2014 at 21:18
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    @DavidRicherby You're missing the point. Without the 'Oxford Comma', it's not incorrect, it's a different sentence - John, Jill are people who, along with my parent, disagree. I'm not sure if you're seriously suggesting an invented double-dash construct instead.
    – OJFord
    Commented Aug 22, 2014 at 21:27
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    @OllieFord If you write "I know people who disagree: my parents, Jill and Bob", I can't tell if you use Oxford commas and you mean "My parents are called Jill and Bob; they agree" or you don't use Oxford commas and you mean "Jill, Bob and my parents disagree." Conversely, if you wrote "My brother, Jim, and Fred", I can't tell if you're using Oxford commas and you mean "Jim, who is my brother, and Fred" or you don't use Oxford commas and you mean "My brother and Jim and Fred." Oxford commas can both resolve and create ambiguity and cannot be parsed unless you know whether the writer uses them. Commented Aug 22, 2014 at 21:51
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    @DavidRicherby: I would leave off the comma before Jim if he was my brother. I'm not sure how I would interpet "My brother, Jim and Fred". If it had been "My brothers, Jim and Fred" I would think it was talking about my two brothers, while "My brothers, Jim, and Fred" would be Jim, Fred, and my brothers. If I wanted "Jim" to be a parenthetical identification of "my brother", I would use parentheses rather than commas to delineate it "My brother (Jim) and Fred" or "Joe, my brother (Jim), and Fred".
    – supercat
    Commented Aug 23, 2014 at 19:14

I think the key is in how it sounds when read aloud.

When people read a sentence they normally "hear" it as speech with their internal voice (theories on this originally based on Lev Vygotsky's work, and there are even indications that this inner speech has an accent).

A comma translates to a pause in speech, so I think readability will be improved if the pauses are in the correct place.

For example, which would sound better to you when reciting a list of items?

  • I had sausages < pause > bacon < pause > and eggs for breakfast.
  • I had sausages < pause > bacon and eggs for breakfast.
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    Commas do not translate as pauses in speech. They indicate grammatical structure, not rhythm. Commented Aug 22, 2014 at 13:15
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    @DavidRicherby Can you give me an example of a sentence (in English) with a comma / commas where there is no slight pause, break, or change to the rhythm?
    – Franchesca
    Commented Aug 22, 2014 at 14:32
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    @DavidRicherby I think you must be altering the rhythm without noticing. While commas don't exactly correspond to pauses, they are used to make the same groupings that would be made in speech. If the comma was not in any way apparent in speech, it would be unnecessary, since writing transcribes speech.
    – trlkly
    Commented Aug 22, 2014 at 18:03
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    @DavidRicherby: This is perhaps best illustrated by the usage of "a" or "an" depending upon whether the following word would be spoken with an initial vowel sound. Because English wasn't "designed" as a language, but rather evolved, it's not possible to prescribe "rules" in the same way as one could for Java or C++.
    – supercat
    Commented Aug 23, 2014 at 20:29
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    @KenMohnkern I find it absurd that people are freaking out about how commas don't "mean" a pause. What is sentence structure for if it isn't about speech? Why do long sentences sound nicer when broken up with commas, or restructured with full stops? It's because people need to to stop for breath while speaking. Even the internal monologue voice in your head will somewhat stumble over a needlessly long sentence that goes on and on without the kind of pause for breath that a comma might have reasonably allowed you to take had it been present.
    – Franchesca
    Commented Aug 25, 2014 at 8:29

In the olden days, the written word existed principally to allow reading out loud. The comma indicated that the reader should leave a very short pause before going on to the next word. That pause is almost imperceptible, but it affects the way the hearer understands what has been said. The Oxford comma is no exception.

Without that pause the list is subject to misinterpretation.


If I look specifically at your example of that list, I'd avoid using that type of serialization entirely, if at all possible. I'd use a simple unordered list and put those below each other in a text.

If you need to use inline serialization, you should try write your sentence to avoid the ambiguity entirely, or at least the serial comma. In this case, I'd use an ampersand (&) instead of the word and when talking about services and solutions in a text.

  • This is my favourite answer. And a list can be formatted inline. Commented Aug 26, 2014 at 13:22

An ampersand rather than a comma would help solve this and work in menus and lists where commas wouldn't.

Ampersands are used as replacement for "and" with company names, common abreviations etc that are intended to be read as one phrase. So "Services & Support" is more clearly a single option than "services and support".

Of course if you're relying on this level of grammar-finery to make your navigation clear you probably have other problems....

  • In the OP's example there is more than an ampersand. There is a full "and". Yet it still reads as if Obama and Castro are getting married, because there is no comma before the "and." A comma should have been included before this particular "and", because there would have been a pause in speech which would have indicated that same-sex marriage was a completely different point from the Obama-Castro handshake. Commented Aug 25, 2014 at 12:11
  • The ampersand trick is neat. With the ampersand, the writing gets clarified but there is an ambiguity in speech. Commented Aug 26, 2014 at 13:12

Yes, the Oxford comma improves readability, but it's no panacea for careless or odd composition. Like any other great power, it can be used irresponsibly.

Some of these examples here are red-herrings, precisely because there are several good ways to improve understanding, regardless of the commas. There are problems you shouldn't try to solve with the Oxford comma. For instance, there's no confusion in "I gave gifts to my father, Jim and to Beth." Or, we're totally clear with "I gave gifts to Beth and my father, Jim." Why try to cram those sentences into a series of commas? Or again, why not use classifiers for everyone? Or, who cares what your father's first name is?

It's asinine to look for the Oxford Comma to solve all problems. But when used in a standard list of independent items, it does indeed improve readability. Just don't throw it around willy-nilly, without considering potentially better options, and then blame the poor Oxford comma.

(BTW, here's some gratuitous humor involving the Oxford comma, strippers, and Stalin. It's actually a pretty good example of a use-case where it clearly improves readability.)

  • Your sentence "I gave gifts to my father, Jim and to Beth." is awkward. It makes no sense to me. Commented Aug 26, 2014 at 14:33
  • Lots of formal syntax that is technically grammatical has come to sound awkward or stilted. I believe that sentence fits the bill. Yet, I still find it difficult to misunderstand. Given that we're talking about ambiguity, what alternate interpretation do you see?
    – XML
    Commented Aug 26, 2014 at 14:41
  • My interpretation is that the sentence misses symmetry. It looks that an apposition for "my father" starts but never ends. The sentence is not correct. It means nothing to me. Commented Aug 27, 2014 at 8:46

Consult your company's style guide. In my own writing I always use it because I think it improves clarity. In my business writing I never use it because the companies I've worked for had style guides in place that specified not to use it.

Don't have a style guide? Not gonna make one? Then just pick a style and be consistent. (And have as many coworkers be consistent as possible.)

In your example, you could improve clarity without the serial comma by quoting each item: You may have "Home," "Products," "Solutions," "Services and Support" and "About Us." (Yes, the commas and periods go inside the quotes.)

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    Why do the commas and periods go inside the quotes? They're not part of the thing you're trying to quote.
    – Nzall
    Commented Aug 22, 2014 at 12:40
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    It's a typographic standard, developed over the centuries. I don't have a logical reason for it; I suspect we do it because commas and periods look better tucked inside the quotes. (Look at professionally typeset works - NYT, books, magazines - and you'll see it all the time.) Commented Aug 22, 2014 at 12:51
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    Note, the "standard" re: quotes is arguably incorrect in a number of contexts (like programming) where a piece of punctuation can make something totally wrong. I personally consider it incorrect everywhere, and refuse to use it, unless the punctuation is part of the quote.
    – cHao
    Commented Aug 22, 2014 at 13:28
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    I think the remark on punctuation is just mistaken. In the sentence ("Yes," she said, "I do.") the punctuation can go inside the quotes, fair enough. In the sentence: (A "selfie", as the youngsters call it, is a photo of yourself) it can't, although you could use italics instead to avoid the issue. When listing labels in quotes there should be nothing in the quotes other than the exact label text. I used parentheses to quote my examples there because I really don't think that nesting different types of quotation marks would improve clarity in this case! Commented Aug 22, 2014 at 14:00
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    I despise punctuation in quotes. It's disgusting. I believe it originates in the US, but I certainly know people here (UK) that claim it's correct. Ugh.
    – OJFord
    Commented Aug 22, 2014 at 21:30

Foremost, I think we need to recognize what an Oxford comma is. It's only used in the case of lists of at least three items. All of these use-cases about parents' names are absurd and wrong, regardless of your grammatical background. Your parents, Bob and Alice, never have commas after the first name. If it's a really big deal, you could replace parenthetical commas with actual parentheses or reorganize the sentence. Bob and Alice, my parents, won't get confused if you avoid the conjunction.

As far as readability goes, it's fuzzy. This discussion has involved numerous complicated sentence structures where it's complicated with or without the comma. Using it will not improve readability nearly as much as restructuring the sentence would. As we've found numerous examples to demonstrate, using the comma in a parenthetical phrase already enclosed in commas is going to be confusing. However, not using it will probably also be confusing because of so many commas nearby anyway.

Regarding the original example of headlines, an Oxford comma reduces ambiguity and it's probably a good idea to use it in such a case where list items might include conjunctions. However, it's not better in all cases and sentence structure will have a bigger impact if it's not a straight-forward list.

  • Welcome to the site, @Michael. At the moment, the first two paragraphs of your post appear to be a commentary on other answers rather than an answer. The third paragraph does address the question, but it reads as only opinion; it would be stronger if can provide some evidence. Commented Aug 24, 2014 at 5:23

Objective evidence strongly suggests that the Oxford comma does not consistently and universally help readability. By this, I mean that there is a strong cross-Atlantic difference in the use of commas in general and the Oxford comma in particular: modern American editors use them much more often than modern British editors. (I have no idea what the rest of the English-speaking world does.) When I started reading British books as a kid -- I mean ones imported from Britain, not ones by a British author typeset here in the US -- I got confused by all the "missing" commas that I expected from American literature. But when I read literature where every possible comma is included in long sentences, I get confused by the "extra" commas. British readers on the whole, I imagine, get confused if there are more commas than they were used to seeing when they learned to read and generally prefer the versions without Oxford commas the same way I prefer versions with them.

If one style of comma usage were universally superior, style guides in Britain and the US would long ago have come into line as editors became frustrated by years of "hard-to-read" text.

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