Oxford comma
The Oxford comma (or serial comma) is the optional comma placed before 'and' or 'or' at the end of a list of three or more items: 'coffee, tea, and juice.' Both using it and dropping it are correct in standard English; the only rule that matters is staying consistent throughout the same piece of writing.
How to use oxford comma
What is the Oxford comma?
The Oxford comma is the comma placed directly before the final 'and' or 'or' in a list of three or more items. 'Bread, cheese, and grapes' uses it; 'bread, cheese and grapes' doesn't, both are grammatically correct.
It takes its name from Oxford University Press style guides, which have long recommended it, though it's used (or dropped) across both British and American English depending on the publication.
- The bag contained a notebook, a pen, and a bottle of water.Oxford comma before 'and'
- The bag contained a notebook, a pen and a bottle of water.no Oxford comma, equally correct
When does the Oxford comma prevent ambiguity?
In most lists, the comma is a style choice with no effect on meaning. But when a list item could be misread as describing another item, the Oxford comma removes the ambiguity by clearly separating them.
This is the strongest practical argument in favour of always using it: a missing Oxford comma can occasionally turn a simple list into a confusing sentence.
- I'd like to thank my parents, Marie Curie, and my tutor.three separate items, clear thanks to three people
- I'd like to thank my parents, Marie Curie and my tutor.without the comma this could misread as 'my parents' being Marie Curie and my tutor
- The exhibition featured photos of the mountains, a local farmer, and his dog.comma keeps the farmer and his dog as separate items
Do you need the Oxford comma in IELTS writing?
No. IELTS does not require or prefer either style; examiners accept lists with or without the Oxford comma, as both are standard in different varieties of English. What matters for Grammatical Range and Accuracy is that you punctuate lists correctly and consistently, not which style you pick.
Pick one approach for your whole test and stick to it; switching between the two styles within the same piece of writing can look inconsistent, even though neither style is wrong on its own.
- The report analyses cost, efficiency, and sustainability.consistent Oxford-comma style
- The plan improves transport, reduces emissions and lowers costs.consistent no-Oxford-comma style
Does the Oxford comma apply to two-item lists?
No. The Oxford comma only concerns lists of three or more items. A list of exactly two items joined by 'and' or 'or' never takes a comma before the conjunction, regardless of which style you otherwise prefer.
- She ordered soup and salad.only two items, no comma before 'and'
- She ordered soup, and salad.a comma before 'and' with only two items is always wrong → soup and salad
Does the same choice apply to a list of clauses?
The same optional-comma choice extends to a list of three short clauses, each with its own verb: you may add a comma before the final 'and', or leave it out, as long as you're consistent within the sentence and the wider text.
- He booked the flights, packed his bags, and left for the airport.
- He booked the flights, packed his bags and left for the airport.also correct, no Oxford comma
Common mistakes with oxford comma
Find what is wrong in each one, then open it to check.
1We visited Paris, Rome, and, Berlin.What's wrong? Show the fix
We visited Paris, Rome, and Berlin.
The Oxford comma goes before 'and', not after it; there's only ever one comma at that position.
2I ordered tea, and coffee.What's wrong? Show the fix
I ordered tea and coffee.
The Oxford comma only applies to lists of three or more items; a plain two-item list never takes a comma before 'and'.
3The menu offers soup, a sandwich with fries and a drink.What's wrong? Show the fix
The menu offers soup, a sandwich with fries, and a drink.
Without the Oxford comma before 'and', it's unclear whether 'fries and a drink' are both part of the sandwich item, the comma separates the two final items clearly.
4This report is dedicated to my professor, an inspiring mentor and my closest friend.What's wrong? Show the fix
This report is dedicated to my professor, an inspiring mentor, and my closest friend.
Without the final comma, the sentence could be misread as describing only one person ('my professor, an inspiring mentor') followed by a second, rather than naming three separate people; the Oxford comma removes the ambiguity.
5We need volunteers, staff and, managers for the event.What's wrong? Show the fix
We need volunteers, staff and managers for the event.
A comma should never sit directly after 'and' inside a list; it belongs before the conjunction, not after it.
Practise
Write your own
Write a sentence of your own with oxford comma, about you, your studies or your town.
Oxford comma in IELTS
Speaking
- Long spoken lists ('I enjoy hiking, cycling, and reading') naturally include a short pause before the final item; that pause is the spoken version of the Oxford comma, and it helps the examiner follow a longer list clearly.
- Either listing style is fine in Speaking; what examiners actually listen for is that you can produce longer, well-organised lists at all, a marker of lexical and grammatical range.
Writing
- Choose one list style (with or without the Oxford comma) at the start of your Task 2 essay and use it throughout; consistency is what Grammatical Range and Accuracy rewards, not the choice itself.
- In Task 1, lists of data categories ('imports, exports, and re-exports') benefit from the Oxford comma whenever the category names could otherwise blur together, improving clarity for the reader.