Grammar Guidelines For Every Correct Use of the Apostrophe

Subscribe to Blog Upper ButtonWhen it comes to grammar, my biggest pet peeve is the misuse of the apostrophe. Not a week goes by where I don’t see things like “cat’s for sale” and “free CD’s.”

Clearly, I spend most of my time perusing the community classifieds.

One of my running routes passes by a house with an enormous stone in its front yard carved with the family name: The Bradley’s.


The rule is that if you don’t do anything about something, you can’t complain about it. So, this is me doing something. I’m setting the record straight on how to correctly use the apostrophe so that this helpful punctuation mark is no longer misrepresented.

You Can Use an Apostrophe for a Contraction

The apostrophe is one of the few punctuation marks that you can almost see when you speak a word that includes it. And because we speak with contractions frequently in casual conversation, this is an instance where we rarely forget to include the necessary punctuation mark.

In short, a contraction is when multiple words are combined to form one word. In writing, the apostrophe stands in where the missing letters drop off.


  • It must be five o’clock
  • Who doesn’t love ice cream?
  • I haven’t seen my cousins in years.
  • She’s leaving for work in ten minutes.

For a full complication of contractions, I recommend checking out this list.

You can Use an Apostrophe For Single Noun Possession

An apostrophe + -s ( ’s ) added to the end of the single noun shows the possessive form of that noun, even for proper nouns.


  • Ruby’s farm is thirty minutes from the expressway.
  • The family dog destroyed the child’s homework.
  • The pediatrician’s schedule is already booked for next week.

How About a Single Noun Ending with an -S?

Yes, you should use an apostrophe for a single noun that happens to have the last letter of -s. However, how you apply the apostrophe depends on your style guide.

  • MLA style says you just add an apostrophe after the -s belonging to the spelling of the single noun: The platypus’ tail.
  • Chicago style says to add an apostrophe and an -s at the end: The platypus’s tail.
  • AP style says add to an apostrophe and an -s at the end, unless the next word starts with an -s: The platypus’s tail. The platypus’ shiny fur.

What do you do? Commit to the style guide within your piece of writing and stay consistent with your use of the apostrophe in these instances.

You Can Use an Apostrophe For Plural Noun Possession

When you want to form the possessive for a plural noun that already ends in -s, you only add an apostrophe. That’s it.


  • The boys’ tree fort has a sign that says, “no girls allowed.”
  • You can find the Robertsons’ house on Blueberry Boulevard.
  • The graduate students’ test will count for 33% of their final grade.

Forming the possessive of plural nouns not ending in -s is also easy. Simply add an apostrophe and -s at the end of the word:

  • That store does not carry men’s shoes.
  • Our women’s basketball team will compete in the finals this Friday.
  • We purchased a dozen books from the children’s book store down the street.

Can You Use an Apostrophe for Possessive Pronouns?

One of the biggest grammatical mistakes I find myself fixing is when a writer makes a contraction out of it’s as if that’s the possessive form of it.

It is not.

Possessive pronouns already show ownership, so an apostrophe and -s is not necessary. You’d write the pronoun as is:

  • Its
  • His
  • Hers
  • Theirs
  • Yours
  • Ours

This is not the case for indefinite pronouns when it is vaguely defined as to who the pronoun is actually referencing:

  • Somebody’s bracelet was found in the bathroom.
  • Who will end up showing up to work today is anybody’s guess.
  • One’s judgement must be used when receiving constructive criticism.

How About When Two Nouns Possess the Same Thing?

Of course. All you have to do is add an apostrophe and -s to the last noun listed.


  • Marsha and Colleen’s birthday party was a blast.
  • You can find the hidden presents in Mom and Dad’s closet.

Don’t forget that when two or more nouns possess something separately, they each receive an apostrophe and -s at the end of the noun.


  • Marsha’s and Colleen’s birthday parties were a blast (they each had a separate birthday party).
  • You can find the hidden presents in Mom’s and Dad’s closets (they each have a separate closet).

Can You Use an Apostrophe to Form a Plural?

Absolutely not. Unless you’d like for me to create a meme of myself rolling my eyes.

An apostrophe is not needed to indicate the plural form of a word. In most cases, an -s or -es is required to change a noun from singular to plural, including dates, acronyms and family names:

  • I can’t believe these DVDs still play without skipping.
  • My school project focuses on the fashion of the 1930s.
  • We invited the Hendersons over for dinner.

In rare cases, you may need to add an apostrophe and -s to imply the plural forms of certain letters and expressions not commonly referenced in the plural, such as “dot the i’s and cross the t’s”.

Did I miss a rule? Feel free to update my advice in the comments section below.

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