The 3 Apostrophe Rules You Need to Know for the SAT/ACT

Bonus: PrepMaven’s Apostrophe Rules Worksheet with FREE Practice Questions

You only need to know 3 apostrophe rules to succeed on ACT English or SAT Writing & Language.

What’s more, apostrophe questions are relatively rare on both tests.

Yet your fluency in apostrophe usage can get you that much closer to a competitive score on these sections. Remember: every point matters.

In this post, we walk you through the 3 simple apostrophe rules tested on the ACT/SAT. We also give you access to our Apostrophe Rules Worksheet, which includes guided examples, free practice questions, and explanations.

You can download this worksheet below now.

Here’s what we’ll be covering in this post:

Apostrophe Usage in a Nutshell

We use apostrophes in the English language to show one of 2 things:

  1. Contraction
  2. Possession


Most students are fairly comfortable using contractions because they appear frequently in casual speech. Contractions are compressions of two words, as in the following examples:

  • couldn’t (contraction of could and not)
  • won’t (contraction of will and not)
  • I’d (contraction of and would)
  • there’s (contraction of there and is)
  • it’s (contraction of it and is)

Why do we use contractions? They can be useful for shortening and simplifying speech, although many high school English teachers encourage their students to avoid using contractions in academic writing.

With contractions, apostrophes serve as a visual indicator of the “bridge” between the two words.

Apostrophe Rules on the SAT _ ACT (1)


We also use apostrophes as a way of showing ownership or possession. Apostrophes serve as visual indicators of who or what is the “owner” and who or what is the “possession.”

Here are a few examples of possession in action:

  • Margot’s thesis project –> the owner is “Margot” and the possession is the “project”
  • The children’s book section –> the owner is “children” and the possession is “book”
  • The students’ questions –> the owners are “students” and the possession is “questions”
  • The Jones’ yard –> the owners are “the Jones” and the possession is “yard”

Notice how the possession always appears after the owner in these examples.

It’s also possible to show ownership by using possessive pronouns like their, my, or her. We discuss possessive pronouns (and other kinds of pronouns!) in our comprehensive Guide to Pronouns on the ACT and SAT post.

Apostrophes and the SAT/ACT

Students will encounter apostrophe questions on these 2 sections:

  • ACT English
  • SAT Writing & Language

As we’ve mentioned in our other grammar posts, however, knowledge of apostrophe rules can be helpful elsewhere, such as the optional essay section on both tests. Essay graders will be checking for effective use of English conventions in your response, so proper grammar can help you achieve a higher essay score.

Apostrophe questions appear relatively infrequently on both tests, although they are still worth preparing for. Here’s a breakdown of what you can expect to see on either test:    

Apostrophe Questions on the ACT Apostrophe Questions on the SAT
1-2 0-2
*Based on analysis of officially released ACT and SAT practice tests

When you do see an apostrophe question on ACT English or SAT Writing & Language, you’ll largely have to worry about possession rules. Your knowledge of contraction is only tested in one very specific way, which we discuss in the next section.

How can you tell that you’re dealing with an apostrophe question? You will likely see contractions and/or apostrophes in the answer choices!

The 3 Apostrophe Rules You Need to Know

Now it’s time to take a deep dive into the 3 apostrophe rules you’ll need to know for ACT English and SAT Writing & Language. 

Rule #1: Its vs. It’s

This may sound like an obvious rule to some students, but both the SAT and ACT are very likely to test your knowledge of the difference between “its” and “it’s.” 

The difference is that “its” is the possessive form of the pronoun “it,” while “it’s” is a contraction that really means “it is.”

its it’s

the possessive form of “it”

The dog wagged its tail.

the contraction of “it is”

I think it’s going to rain today.

If you see its, it’s, and/or both of these in your answer choices, read carefully! We recommend reading “it’s” as “it is” to help with your elimination process on these types of questions.

Rule #2: Add ‘s to singular nouns showing ownership

To show ownership with a singular noun, simply add an ‘s to the end of that noun. This is likely to be the easiest possession rule for students to remember.

Check out these examples of singular noun possession:

  • Dmitri’s dreams
  • The cat’s favorite window sill
  • The Earth’s curvature
  • My mother’s phone calls
  • The podcast’s listeners

How can you tell if a noun is singular? There should be only one of that particular noun. For example, there is only one Dmitri, one cat, one Earth, etc., in the sample phrases above.

Rule #3: Add a single apostrophe to the end of plural nouns ending in “s”

If you’re showing ownership with a plural noun that ends in “s,” all you need to do is add an apostrophe to the end of that noun. Here are some examples of plural noun possession:

  • The books’ covers
  • The sidewalks’ cracks
  • My teachers’ curriculum
  • The mountains’ peaks
  • The computers’ hardware

Besides the fact that these plural nouns end in “s,” you can tell that they are plural because there is more than one of each. From the examples, we know that we are discussing more than one book, sidewalk, teacher, mountain, and computer.

Not every plural noun ends in “s,” however, and it’s possible to have a singular noun that ends in “s.” We discuss what to do in these scenarios below.

Singular Nouns Ending in “S”

What about singular nouns that end in “s,” including proper nouns like Chris? You still follow the rule of adding an ‘s to these nouns. Here’s what that would look like:

  • Chris’s classes
  • The iris’s stamens
  • The sea bass’s flavor
  • James’s preferences
  • Nicholas’s parents

We know it feels awkward, but that’s the rule! The only exception to this is with proper nouns that have historical and/or biblical associations, like “Moses” or “Jesus.” In these instances, all you need to do is add an apostrophe to the end:

  • Moses’ leadership
  • Jesus’ teachings

However, don’t worry about this exception–it won’t be tested on the ACT or the SAT.

Plural Nouns That Don’t End in “S”

Yes, you can have a plural noun that doesn’t end in “s”! What happens if you want to show possession with one of these nouns? All you need to do is treat it like a singular noun: add an ‘s to the end.

Check out these examples:

  • The children’s games
  • People’s voting habits
  • Women’s rights
  • Sheep’s wool
  • The phenomena’s relevance

In the next section, we’ll discuss how to apply these 3 apostrophe rules to SAT Writing & Language and ACT English punctuation questions.

You can apply this 4-step strategy easily to the practice questions included in our free Apostrophes Worksheet.

Apostrophe Rules: Our 4-Step Strategy for Applying Them

When you encounter an apostrophes question on ACT English or SAT Writing & Language, follow these strategic steps:

  1. Read the full context
  2. Identify if you’re dealing with a case of contraction or possession
  3. If possession, identify who/what is owning who/what & apply apostrophe rules
  4. If contraction, eliminate rule-breakers and plug in your final choice

We’ll apply these steps to 2 sample apostrophe questions from an ACT and SAT official practice test.

Example 1: ACT Apostrophe Question

ACT Punctuation_Apostrophes Question
Source: ACT Official Practice Test #1

1. Read the full context

The apostrophes in the answer choices indicate that we will most likely have to apply our knowledge of apostrophe rules to this question. The full context tells us more about Jones, an individual who became a strong advocate of a particular movement.

2. Identify if you’re dealing with a case of contraction or possession

This may seem tricky, but close analysis of the answer choices and underlined portion indicate that we’re dealing with possession. Three of the answer choices contain the possessive noun movement’s and two contain possessive forms of the noun advocates.

3. If possession, identify who/what is owning who/what & apply apostrophe rules

Context tells us that movement is the “owner” of advocatesMovement is a singular noun, so we will need to add an ‘s to the end to show proper possession: movement’s. We can now eliminate answer choice J.

Some of our answer choices have apostrophes associated with the plural noun advocates, but advocates in this context does not “own” anything. We can eliminate answers F and G and choose answer H.

Here’s how the corrected sentence would look: Jones, however, became one of the movement’s most powerful and controversial advocates.

Example 2: SAT Apostrophe Question

Source: CollegeBoard SAT Official Practice Test #1

SAT Punctuation_Apostrophes Question

1. Read the full context

The answer choices indicate that we might have to apply our knowledge of apostrophe rules, as two of the answers include apostrophes. The word “major” also appears in different forms, so we might have to apply additional grammar rules (a common case on both ACT English and SAT Writing & Language).

Context tells us that this sentence describes philosophy majors and their professional pursuits.

2. Identify if you’re dealing with a case of contraction or possession

This is a bit of a trick question, as close analysis of the sentence in question tells us that we are dealing with neither contraction nor possession! That’s because students is simply a plural noun and does not “own” anything. The phrase majoring in philosophy is describing these particular students.

We can immediately cross off answers A and D, as these both have apostrophes in them. The appropriate form of major is majoring, as majoring in philosophy is describing the students. Our correct answer is B.

Some of you might be thinking, Hold up–why is this an apostrophes question? It’s an apostrophes question because it does require knowledge of apostrophe usage, even if we didn’t end up choosing an answer choice with an apostrophe! In fact, this is very typical of ACT English and SAT Writing & Language questions.

Download PrepMaven’s Apostrophes Worksheet

If you want test-like practice with apostrophe rules, we’ve got you covered. 

Our free Apostrophe Rules worksheet has everything you need to solidify the apostrophe rules and 4-step strategy discussed in this post.

Apostrophes_SAT and ACT Grammar

Here’s what you’ll get:

    • A recap of the apostrophe rules and 4-step strategy discussed in this post
    • Guided examples of apostrophes questions from official practice tests
    • 10 FREE test-like practice questions with detailed answers/explanations 

Kate_Princeton Tutoring_AuthorBio Kate M.

Kate is a graduate of Princeton University (B.A. in English Literature and Interdisciplinary Humanities) and Boston University (M.F.A in Creative Writing). Over the last decade, Kate has successfully mentored hundreds of students in all aspects of the college admissions process, including the SAT, ACT, and college application essay. She is a Master tutor at Princeton Tutoring.