Serial (Oxford) comma
Last reviewed: 2026-06-21
The serial comma — also called the Oxford comma — is the comma placed immediately before the final coordinating conjunction ("and" or "or") in a list of three or more items, as in "red, white, and blue". Whether to use it is a matter of style: some guides require it, others omit it.
What it is
In a list of three or more items, the serial comma is the one before the closing "and" or "or". With it: "We invited the lawyers, the senators, and the donors." Without it: "We invited the lawyers, the senators and the donors." Both are widely used. The Chicago Manual of Style, most book and academic publishers, and US English convention generally favor the serial comma; the Associated Press (AP) style used by many newspapers omits it except where needed to avoid confusion. British usage varies, though it is associated with the Oxford University Press, which is where the "Oxford comma" name comes from.
The strongest argument for the serial comma is that it removes ambiguity. The often-cited example "We invited the strippers, JFK and Stalin" can be read as inviting two people who are strippers; "the strippers, JFK, and Stalin" cannot. The argument against is brevity, and that the extra comma is occasionally unnecessary when the meaning is already clear.
Why it matters for website copy
The serial comma is a classic example of a choice where consistency matters more than the choice itself. There is no universally correct answer — but mixing both styles within one site is a genuine error of consistency. A site that writes "fast, simple, and secure" on the homepage and "fast, simple and secure" on the pricing page reads as if two people wrote it without coordinating, which they probably did.
Because lists appear constantly in web copy — feature lists, benefit lists, navigation, footers — the serial-comma decision recurs on nearly every page, and it is exactly the kind of detail that drifts as a site grows. Deciding the convention once (most often: use it, for the clarity) and applying it everywhere is the practical answer. Where the comma is genuinely needed to prevent a misreading, it should be used regardless of the house style, because clarity outranks consistency.
Common mistakes
The most common mistake is not deciding at all, so the comma appears on some pages and not others. Another is omitting it in a sentence where its absence creates real ambiguity — the case where even AP style would add it back. A third is treating the rule as a matter of correctness and "fixing" copy that was deliberately following a different, internally consistent convention; the test is whether the site agrees with itself, not whether it matches your personal preference.
Related terms & reading
Related reading: consistency matters more than the choice.
Frequently asked questions
Is the Oxford comma grammatically required?
No. It is a style choice, not a grammar rule. Some style guides (like Chicago) require it; others (like AP) omit it except to avoid ambiguity. Both styles are correct. What matters is choosing one and using it consistently — and adding the comma whenever leaving it out would create a genuine misreading.
Is the Oxford comma the same as the serial comma?
Yes. They are two names for the same thing: the comma before the final "and" or "or" in a list of three or more items. "Oxford comma" comes from its association with Oxford University Press; "serial comma" describes its position in a series.