Comma Before Or | Rules & Examples
You need a comma before ‘or’ when it connects two independent clauses. These are clauses that could stand alone as full sentences because each contains its own subject and verb.
But you shouldn’t use a comma before ‘or’ when it connects two verbs with the same subject.
When to use a comma before ‘or’
You can recognise that the conjunction ‘or’ is connecting two independent clauses (and thus needs to be preceded by a comma) when the two clauses have separate subjects and verbs.
Note that this applies even if the two subjects and/or the two verbs refer to the same thing or are identical.
Did it arrive yesterday, or did it arrive today?
But it’s better to simplify such repetitive phrasings by leaving out the second subject and, if the verbs are the same too, the second verb. In these versions, you don’t need the comma.
Did it arrive yesterday or today?
Most style guides suggest that it’s fine to omit the comma when the two independent clauses are short and closely related. The comma is optional in these cases.
Either she goes, or I go.
You also need a comma before ‘or’ in situations where it’s preceded by something that’s normally surrounded by commas, like a nonrestrictive relative clause.
When not to use a comma before ‘or’
When ‘or’ is not joining two independent clauses but two individual words or short phrases (e.g., verbs, nouns, adjectives, adverbs, pronouns), no comma should be used.
- Was it Juan, or David who said that?
- Was it Juan or David who said that?
- He wasn’t sure whether he’d drive to work, or take the bus.
- He wasn’t sure whether he’d drive to work or take the bus.
- Do you find Sandra friendly, or overbearing?
- Do you find Sandra friendly or overbearing?
An exception is at the end of a list of three or more items. Before the conjunction (whether it’s ‘or’ or ‘and’), you can choose to add a comma. This is called the Oxford comma (or serial comma); it’s recommended by most style guides, but it’s not mandatory.
Is there ever a comma after ‘or’?
There’s usually no comma after ‘or’. Even when you start a sentence with ‘or’, it’s generally considered incorrect to place a comma after it.
- Or, you could just tell me what you think.
The only time when a comma appears after ‘or’ is when a phrase called an interrupter comes immediately after it. An interrupter is a phrase used to add emphasis or qualify a statement, and it’s usually surrounded by commas.
I don’t have much time or, to be honest, motivation.
Worksheet: Comma before ‘or’
Try completing the following worksheet to see if you understand when you need a comma before ‘or’. Insert commas into each sentence wherever you think they’re needed, and then check your work against the answers provided.
- Did John already go home or is he staying here overnight?
- I’m not sure whether the car was gray or green.
- Would you like tea coffee or water?
- We’ll go to the beach or if the weather isn’t good to the museum.
- I can check with her for you. Or you could ask her yourself.
- Did John already go home, or is he staying here for the night?
- A comma is added here because the conjunction ‘or’ connects two independent clauses with separate subjects and verbs (‘Did John’ and ‘is he’).
- I’m not sure whether the car was grey or green.
- No comma is used here because ‘or’ connects two individual adjectives (‘gray’ and ‘green’).
- Would you like tea, coffee(,) or water?
- This is a list of three items (‘tea’, ‘coffee’, and ‘water’). The comma between the first two items is needed to separate them. The comma before ‘or’ is an Oxford comma. This comma is optional but recommended by most style guides.
- We’ll go to the beach or, if the weather isn’t good, to the museum.
- A comma is used after ‘or’ here to set off the qualifying interrupter ‘if the weather isn’t good’. Another comma appears after the interrupter.
- I can check with her for you. Or you could ask her yourself.
- No commas are needed here. When ‘or’ introduces a new sentence, it shouldn’t be followed by a comma.
Other interesting language articles
If you want to know more about commonly confused words, definitions, common mistakes, and differences between US and UK spellings, make sure to check out some of our other language articles with explanations, examples, and quizzes.
Sources for this article
We strongly encourage students to use sources in their work. You can cite our article (APA Style) or take a deep dive into the articles below.
This Scribbr articleCaulfield, J. (2023, March 20). Comma Before Or | Rules & Examples. Scribbr. Retrieved 9 December 2024, from https://www.scribbr.co.uk/comma/comma-with-or/
Butterfield, J. (Ed.). (2015). Fowler’s dictionary of modern English usage (4th ed.). Oxford University Press.
Garner, B. A. (2016). Garner’s modern English usage (4th ed.). Oxford University Press.
