Apostrophes can be deceptively tricky. One of the most common sources of confusion? Knowing when to place an apostrophe after s. Should you write students’ books or student’s books? What about Charles’s car versus Charles’ car?
This guide clears the fog. We’ll walk through the real rules—not myths—behind apostrophes after “s”, using clear examples, usage tips, and a little storytelling. You’ll also learn how to avoid embarrassing mistakes like the notorious grocer’s apostrophe.
What Does an Apostrophe After S Mean?
When an apostrophe follows the letter “s”, it typically shows possession—but the number of people or things involved matters. This subtle difference separates common grammar goofs from confident usage.
Here’s the core idea:
- If a plural noun ends in s, add the apostrophe after the s → dogs’ tails, teachers’ lounge
- If a singular noun ends in s, style guides differ → Chris’s book or Chris’ book
We’ll unpack both cases below.
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Apostrophe After S Rules: The Basics
Let’s get straight to the apostrophe after s rules with practical clarity.
Plural Nouns That End in S
For regular plurals, add an apostrophe after the s to show ownership.
✅ Correct: The cats’ toys were scattered across the floor.
❌ Wrong: The cats’s toys were scattered across the floor.
Why? Because “cats” already ends in s. Plural nouns don’t need an extra “s” after the apostrophe.
More examples of apostrophe after s in plural nouns:
| Plural Noun | Correct Possessive Form | Example Sentence |
|---|---|---|
| dogs | dogs’ | The dogs’ owner is arriving. |
| houses | houses’ | The houses’ windows were tinted. |
| players | players’ | The players’ coach gave a speech. |
Tip: This is called the possessive apostrophe for plural nouns ending in s—a rule that’s consistent across most style guides.
When to Use S’ vs S’s for Singular Nouns Ending in S
This is where things get spicy.
When a singular noun ends in “s”, some people write s’s, others prefer just s’. So which one is right?
Style Guide Apostrophe After S Opinions:
| Style Guide | Preferred Form | Example |
|---|---|---|
| Chicago Manual of Style | s’s | Charles’s bike |
| Associated Press (AP) | s’ | Charles’ bike |
So, if you’re writing:
- For formal academic writing → go with s’s (Charles’s, boss’s)
- For journalism or news → go with s’ (Charles’, boss’)
Both are technically correct—just stay consistent.
Real-Life Examples:
- Singular noun ending in s possessive:
- The boss’s decision was final. (Chicago style)
- The boss’ office was locked. (AP style)
Apostrophe S vs S Apostrophe: What’s the Difference?
This classic grammar puzzle boils down to singular vs plural.
| Form | Usage | Example |
|---|---|---|
| ’s | Singular possessive | The child’s toy |
| s’ | Plural possessive (or some singular nouns ending in s) | The children’s laughter, the teachers’ meeting |
To simplify:
- Use ’s when one person or thing owns something.
- Use s’ when more than one person or thing owns something and the word already ends in s.
Apostrophe After Plural Noun Rules
Let’s break down what happens when we deal with plural nouns:
Regular Plurals (end in “s”):
Just add apostrophe after s.
- The cars’ engines were roaring.
- The girls’ dresses were colorful.
Irregular Plurals (don’t end in “s”):
Add ’s just like singular nouns.
- The children’s toys were everywhere.
- The men’s locker room is closed.
Apostrophe with Names Ending in S
People’s names love to throw curveballs.
Should you write James’s book or James’ book?
Again, it depends on the style you follow.
| Name | Chicago Style | AP Style |
|---|---|---|
| James | James’s | James’ |
| Chris | Chris’s | Chris’ |
| Thomas | Thomas’s | Thomas’ |
Tip: Read it out loud. If it sounds awkward with the extra “s,” you might prefer using just the apostrophe.
Common Apostrophe Mistakes to Avoid
The Grocer’s Apostrophe
This is a legendary grammar blunder. People use an apostrophe to pluralize a word, which is totally incorrect.
❌ Banana’s
❌ Apple’s on sale
✅ Bananas
✅ Apples on sale
Apostrophes are not for plurals—never use them that way.
Other Apostrophe Placement Errors
Let’s clear up some frequent slip-ups:
| Incorrect | Correct | Why |
|---|---|---|
| The Jones’s house | The Joneses’ house | Jones is plural (the family), so s’ applies. |
| The student’s desks | The students’ desks | More than one student owns desks. |
| Its’ tail wagged | Its tail wagged | “Its” is already possessive—no apostrophe needed. |
How to Use Apostrophe After S: Quick Tips
Keep these bite-sized grammar hacks in mind:
- Plural ends in s? → Add apostrophe after s
- Singular ends in s? → Style-dependent: s’s (Chicago) or s’ (AP)
- Irregular plural? → Add ’s
- Don’t use apostrophes to make words plural
- Check if the noun owns something. If not, no apostrophe
Examples of Apostrophe After S in Real Sentences
Seeing real-world examples helps lock the rules in your brain.
Plural Nouns:
- The drivers’ licenses were scanned.
- The horses’ hooves thundered down the track.
Singular Nouns Ending in S:
- The witness’s statement shocked the jury. (Chicago style)
- The witness’ account matched the evidence. (AP style)
Irregular Plural Possessives:
- The children’s playground was noisy.
- The geese’s migration patterns were studied.
How to Remember the Apostrophe After S Difference
Struggling to recall whether to slap on an apostrophe after the s?
Here’s a quick memory aid:
Rule of Thumb:
“If the noun already ends in s and it’s plural—add only the apostrophe. If it’s singular, check your style guide.”
Visual Tip:
Think of apostrophe placement like a backpack:
- ’s → You’re carrying one backpack.
- s’ → A group has shared backpacks.
Apostrophe After S Style Guide Comparison
Different stylebooks have different takes. Here’s a cheat sheet:
| Style Guide | Plural Possessive | Singular Ending in S |
|---|---|---|
| Chicago | cats’ | Chris’s |
| AP (news) | cats’ | Chris’ |
| APA (academic) | cats’ | Chris’s |
Use Chicago for books, essays, and formal writing. Use AP for blogs, news, and digital content.
Final Thoughts on Apostrophes After S
Mastering apostrophes may seem small—but it sharpens your credibility as a writer. Whether you’re editing an article, writing marketing copy, or just leaving a note, these punctuation marks matter.
Remember:
- Apostrophes after s often mark plural possession.
- For singular nouns ending in s, choose s’s or s’ based on your style.
- Never use apostrophes for plurals—ban grocer’s apostrophes!
Get these straight, and you’ll never second-guess your grammar again.
FAQs
When do you use an apostrophe after s?
When a plural noun ends in s and you want to show possession. Example: The dogs’ collars were colorful.
What’s the difference between apostrophe s and s apostrophe?
’s shows possession for a singular noun, while s’ is used for plural nouns that already end in s.
Is it Chris’s or Chris’?
Both can be correct. Chris’s follows Chicago style. Chris’ follows AP style.
What’s the grocer’s apostrophe?
It’s a grammar error where people use an apostrophe to pluralize a word—like banana’s instead of bananas.