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.

Example: Comma before ‘or’ connecting two independent clauses
Joso and I might go to the museum, or we might go to a café.

But you shouldn’t use a comma before ‘or’ when it connects two verbs with the same subject.

Example: ‘Or’ connecting two verbs with the same subject
Did you walk or drive to get here today?
Note
The same rules apply to using commas with the other main coordinating conjunctions: commas before or after ‘and’, commas before or after ‘but’, and commas before or after ‘so’.

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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.

Examples: Comma before ‘or’ connecting independent clauses
Does Koresh like opera, or does he just go along to humor his girlfriend?

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.

Examples: Simplified phrasings with no comma needed
Does Koresh like opera or just go along to humor his girlfriend?

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.

Examples: ‘Or’ connecting two short independent clauses
Either she goes or I go.

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.

Examples: Comma before ‘or’ when it follows a nonrestrictive clause
To swim, John either goes to the pool, which is just down the road from his house, or to the beach.

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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.

Examples: ‘Or’ connecting individual words or phrases
  • 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.

Example: Oxford comma
She didn’t know whether to name the cat Misty, Tiger, or Whiskers.

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.

Examples: Comma after ‘or’
You can call me Samantha or, if you like, Sam.

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.

  1. Did John already go home or is he staying here overnight?
  2. I’m not sure whether the car was gray or green.
  3. Would you like tea coffee or water?
  4. We’ll go to the beach or if the weather isn’t good to the museum.
  5. I can check with her for you. Or you could ask her yourself.
  1. 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’).
  1. 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’).
  1. 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.
  1. 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.
  1. 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.

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    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 article

    Caulfield, J. (2023, March 20). Comma Before Or | Rules & Examples. Scribbr. Retrieved 22 February 2024, from https://www.scribbr.co.uk/comma/comma-with-or/

    Sources

    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.

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    Jack Caulfield

    Jack is a Brit based in Amsterdam, with an MA in comparative literature. He writes for Scribbr about his specialist topics: grammar, linguistics, citations, and plagiarism. In his spare time, he reads a lot of books.