Do You Need the Oxford Comma?

The Oxford comma sits at the center of one of the great debates of the English language. This punctuation mark — the comma often used before “and” in a series — inspires surprisingly strong opinions, dividing journalists, teachers, editors, and authors. In recent years, the debate over its usage has become something of a marker of grammar cred. While some consider it essential for clarity, others label it as clutter. So, do you really need the Oxford comma? Here’s what grammar rules, style guides, and history have to say.

Also called the serial comma, the Oxford comma is placed immediately before the conjunction (usually “and” or “or”) in a series of three or more terms. For example, “My favorite book genres are mystery, historical fiction, and dystopian.” The final comma in the series, just before “and,” is the Oxford comma.

This comma has been used (and omitted) throughout English history, though it was not called the Oxford comma until the early 20th century. In 1905, Horace Hart, a printer for Oxford University Press, laid out a new requirement for his employees: They must include a final serial comma before the last item in a series. Because OUP was highly influential, the comma earned a nickname tied to the university. However, not all printing presses and grammar authorities followed suit — and thus the controversy began.

Today, usage of the Oxford comma remains mixed. Several major American style guides require it, including Chicago, MLA, and APA. The Associated Press (AP) Stylebook — the standardized style for journalism in the U.S. — generally does not. (Word Smarts primarily follows AP style, with a few notable exceptions, including using the Oxford comma.) Interestingly, the University of Oxford Style Guide — distinct from Oxford University Press — does not require it unless it is needed to prevent ambiguity.

Where does that leave questioning writers? Both options are grammatically correct in modern English, so if you aren’t following a specific style guide, it’s up to your personal preference whether or not to include the Oxford comma. Let’s take a closer look at when you might need it and why you would omit it.

As mentioned earlier, the Oxford comma was in use long before Horace Hart’s decree. For example, it appears many times in Mary Shelley’s famous 1818 Gothic novel Frankenstein: “The starry sky, the sea, and every sight afforded by these wonderful regions seem still to have the power of elevating his soul from earth.”

Sometimes the serial comma doesn’t impact the meaning of a sentence, but it can often enhance readability and prevent ambiguity. For example: “During her commencement speech, she thanked her parents, Cher and Conan O’Brien.” Without the Oxford comma, it reads as though the speaker’s parents are Cher and Conan O’Brien. With the comma, it’s clear she’s thanking her parents, as well as Cher and Conan O’Brien.

This is why many style guides, academic institutions, and book publishers require the comma, as it creates predictable sentence structure. Forgoing the Oxford comma can occasionally create costly or confusing ambiguity in legal or professional writing, which is why some see it as a practical tool rather than unnecessary punctuation.

But for all those who champion the Oxford comma, it has its opposition. Some shrug it off as a redundant mark, citing a preference for cleaner, lighter punctuation. Even Thomas Jefferson decided to forgo the extra comma when he and his committee drafted the Declaration of Independence (1776): “… that among these are Life, Liberty and the pursuit of Happiness.”

In journalism, including AP style, the traditional rule is to omit it unless needed for clarity, as seen in the ambiguous commencement speech example above. Many simple sentences are perfectly understood without it because the conjunction does the heavy lifting: “She went to the grocery store, library and park.”

The omission of the Oxford comma points to a long-standing tradition in the journalism industry, dating back to a time when we received our news in print — not on screens. Printing presses could save space (and paper) by not using the Oxford comma, so it became the norm. But even outside of journalism, omitting the Oxford comma remains a widely accepted approach.

There is no universal rule across all English writing regarding the Oxford comma. Your priority should be to follow the relevant style guide, whether it’s MLA for academics or your company’s grammar rules. If you aren’t following a style guide, the choice is a matter of preference. Whichever you choose, stay consistent throughout your writing, because this tiny mark can leave a big impression.