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Comma before or after “or”: The Definitive Guide

Comma before or after “or”: The Definitive Guide

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Efficacious communication is tantamount to the meticulous analysis of the subtlest linguistic nuances.

These nuances may be found in word meaning, pronunciation, sentence structure, and as well as in non-lexical symbols.

Punctuation marks, such as commas, are non-lexical signs whose principal role is to facilitate reading, either silently or vocally.

Symbols of punctuation serve as prosodic and syntactic cues that aid information absorption, thereby making them a compelling topic of discussion.

The next sections aim to provide definitive guidelines in comma placement before or after the conjunction “or”.

Comma Usage With Or

When is a comma necessary before or after “or”?

A pre-comma is necessary when linking independent clauses, separating the last item in a lengthy series, or using it as the first parenthetical word in a sentence. A post-comma is also essential when using it as the last word in a parenthetical expression or an introductory clause. No commas should be placed on either side when stating two options, listing short items, and linking a dependent clause via ellipsis.


Comma before “or” in more detail

According to stylistic and syntactic guidelines, three circumstances guide the comma placement before or.

The first one is when it coordinates two independent clauses in a compound sentence.

The second is when it is used as the initial element in a parenthetical expression.

The last one is when or is used to link a series of phrases or other relatively lengthy expressions.


“Or” in independent clauses

Or is a coordinating conjunction often used in linking two independent clauses in one sentence.

An independent clause is a simple sentence with a complete thought that can stand alone.

It may contain one or more subjects, one or more verbs, and other complementary constituents.

According to structural form, a sentence composed of two independent clauses is known as a compound type.

Compound sentences are linked by coordinating conjunctions, known as the FANBOYS (for, and, nor, but, or, yet, so).

All compound sentences conjoined by coordinating conjunctions must be separated by a comma before the conjunction to mark clausal independence.

Thus, all the syntactic features above apply to or when linking two independent or main clauses together.

You should start saving now, or you will suffer in the future.
I can either purchase this item now, or I can add it to my cart first.

The key strategy in determining whether the sentence utilizes two independent clauses lies in a simple strategy.

That is, by simply looking for the presence of at least one subject and one verb in each part before and after the conjunction.

In other words, a subject and a verb should be found before the conjunction, and another subject-verb agreement must also be seen after the conjunction.


“Or” in lengthy series

Another syntax-related function of commas is compartmentalizing words in a heavily-constructed sentence.

They guide readers in determining which elements belong where.

In a list of lengthy items, particularly noun phrases, commas serve their function to aid readability.

In a series of at least three, the last item should be linked with a coordinating conjunction, such as and, or, or nor.

For the reasons mentioned earlier, commas are recommended to be placed before the conjunction or in this type of serial list.

Aside from a missed period, other pregnancy symptoms are also marked by increased urination, food aversion, nausea, or a heightened sense of smell.

In the example above, the comma before or bluntly distinguishes the meaning of nausea from a heightened sense of smell.

Without it, the lexical meaning of the word “nausea” could be misinterpreted as the increased olfactory sensitivity during pregnancy.

This type of comma is particularly known as the Oxford comma which is optional in a shorter series, wherein chances of misinformation are rare.


Punctuation with “or” when used as a parenthetical element

In stylistics, a parenthesis refers to comma-encapsulated additional information that is grammatically-dispensable.

Parenthetical speech components aim to define, clarify, digress, understate, or emphasize details.

They serve as rhetoric devices that implicitly assist persuasion, as well as rhythm and intonation.

Commas are necessary to set them apart from the rest of the sentence, and thus, the same rule applies to or when used as the initial parenthetical unit.

He should end up spending the rest of his life in jail, or maybe even worse, for what he did to his own son.

Comma Rules Cheat Sheet


Comma after “or”

Albeit possible, a comma after or would less likely appear than the pre-comma.

The post-comma placement should only take place when or is used either as the final word in a parenthetical expression or a clausal introduction.

Let’s look at each one in detail.



Once again, commas are required by default when writing a parenthetical expression within a sentence.

Therefore,  a comma must come after or when it is the last word in parenthesis.

The second independent clause in a compound sentence linked by coordinating conjunctions, such as and and or, need to be offset with a pre-comma placement.

Parenthesizing provides further clarity and focus to the information being conveyed, and thereby making this stylistic technique salient in writing.


Introductory expression

Introductory elements enhance the initial context intended by writers, giving readers an idea of what comes next.

An introduction may either be a single word, a phrase, or even a clause.

Clauses that introduce a sentence are usually dependent on another independent clause that comes afterward.

They are also commonly headed by conjunctive adverbs and subordinating conjunctions.

Commas may or may not set off introductory elements, which may also be dependent on the length of the expression.

Sentences introduced by short words and phrases may allow comma omission for as long as they do not result in confusion or misinterpretation.

A statutory comma, however, must be inserted every time a dependent clause introduces a sentence.

Hence, when or is the last word in an introductory expression, especially a dependent clause, an after-comma is always mandatory.

When using coordinating conjunctions like but and or, it is necessary to insert a pre-comma, especially in compound sentences.

Regular sentences would not usually require the usage of or as the last introductory word, therefore, the juice isn’t worth the squeeze in this case.


The unnecessary comma before or after “or”

Now that we have fully understood the pre-and-post-comma guidelines, it is also crucial that we know when not to punctuate or with commas.

Three different circumstances dictate the non-comma placement, and these are elaborated in the following sub-sections.


Two short options

Or may also be used for stating two kinds of choices or assumed preferences.

When this happens, commas do not come on either side of or so as not to defeat the function of the conjunction.

Would you like your steak medium or well-done?
Should I book a single or twin room?

Although we would naturally pause after the first option in oral speech, a comma is unnecessary in written text.


Oxford comma

As mentioned earlier, an Oxford comma is the comma that comes before the coordinating conjunctions such as and and or in a serial list or more than two entities.

This is also known as the serial comma which is more prevalently used in British English.

The usage of the Oxford comma is optional in a shorter list because it rarely causes ambiguity.

Thus, the sentence below may or may not have a serial comma before or.

I prefer wearing shirts that are green, yellow(,) or blue.
This shirt is available in small, medium(,) or large sizes.

The Oxford comma may be omitted for as long as it does not create any form of confusion which may lead to misinformation.



Contrary to the function of parenthesis, the ellipsis is a stylistic device that deliberately omits one or more words in a sentence.

The usage of ellipsis supports the non-redundancy of lexical items, particularly when they are clearly implied and easily understood.

When or is used to connect words that would be dependent on the first clause, commas would not be necessary.

Her ultimate wish is to join the Welcome to Jamrock reggae cruise or a stay-all-you-can vacation in Jamaica.

The example above omits some words after the conjunction or for the reason that they can simply be left out without causing any misunderstanding.

If the sentence were complete, it would constitute a compound sentence which would then require a pre-conjunction comma.

Her ultimate wish is to join the Welcome to Jamrock reggae cruise, or she wants to have a stay-all-you-can vacation in Jamaica.



Both stylistic and prescriptive guidelines dictate the placement of punctuation marks in sentences.

Punctuation marks such as commas provide both prosodic and syntactic cues that are a key to the disambiguation of meaning.

By the same token, written language is not only the mere transformation and representation of oral speech into organized lexical units.

It is also a fundamental resource of semiotic discourse elements that further reinforces communication eloquence.

Since the written language is necessary for human civilization to thrive, the need for the efficient use of written linguistic devices is nonetheless indisputable.