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Comma before or after “not to mention” — The Complete Guide

Comma before or after “not to mention” — The Complete Guide

Sometimes, you encounter a group of words that are always used together and that have a different definition from their literal meaning.

These phrases are called “idioms.”

The phrase “not to mention” is sometimes used as an idiom. Knowing when it is an idiom is an important part of identifying whether it also needs a comma.


Do you need a comma before or after “not to mention”?

When “not to mention” comes at the beginning of an independent clause, it should be followed by a comma. As an idiom, in the middle of a sentence, you need a comma before it. When it is not being used as an idiom, no commas should be used.

Identifying when “not to mention” is used as an idiom

The first thing to keep in mind when deciding whether you need commas with “not to

As the negative form of an infinitive, “not to mention” means what it literally appears to mean: that a thing should not be said.

Here are examples of “not to mention” when it is simply acting as a regular negative infinitive in a sentence. In these cases, no commas would be used:

They told me not to mention the bad news.

Lula knew not to mention the weather to Kiran.
He understood that they were not to mention the war.
Many verbs function in this same way. They can be used in their infinitive from plus “not,” and, just as in the above examples, no commas are used:
They were told not to play in the street.
If they ask you not to eat the cake until later, you should do as they say.
It is important to distinguish this usage from the idiom “not to mention,” which has a special meaning.
“Not to mention” as an idiom is used to add and emphasize something in a list of two or

Here are three examples of “not to mention” used in this way:

I can’t believe she has the time and energy, not to mention the money, to remodel the entire house

The risks, not to mention the costs, of starting a new business now mean it is a terrible idea.

I don’t like cooking, cleaning or any kind of domestic work. Not to mention, there were no cleaning supplies in the house anyway.

The first thing to ask yourself when you are deciding whether “not to mention” needs comma is how it is being used in the sentence.

If it is an idiom, you will need a comma before or after it based on where it appears in the sentence.


“Not to mention” as an idiom at the beginning of an independent clause

“Not to mention” at the beginning of a sentence is a more informal way of writing or speaking.

It is also fairly common in casual writing, so while you probably wouldn’t see it in a formal essay, you might see it in a social media post or an email from a friend.

When “not to mention” comes at the beginning of an independent clause as an idiom, it follows a sentence or independent clause that names at least in a list. It adds at least one more item.

Treat it as an introductory phrase, and put a comma after it.

Here are two examples:

Greta was exhausted; not to mention, she hadn’t eaten all day.

We were hesitant to go any further because we’d lost our map and didn’t have any water left. Not to mention, we’d heard this was bear country.

As is always the case with “not to mention,” be sure to distinguish its use as an idiom from other uses.

For example, in the sentence below, it comes at the beginning of the sentence, but here, it is not used as an idiom:

Not to mention the importance of this interview would be a mistake.

Instead, that entire phrase “not to mention the importance of this interview” is acting as the subject of the sentence.

“Not to mention” in the middle of a sentence

More commonly, “not to mention” as an idiom comes somewhere in the middle or near the end of a sentence.

In these types of sentences, it should be preceded by a comma:

We have the skills and the drive, not to mention the ability, to succeed at this task.

She runs into a lot of problems with the poor quality of the soil and the pests, not to mention she knows little about gardening!

Pets can provide companionship and love, not to mention a lot of laughs.