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What is a possessive noun?

The possessive form of a noun shows ownership or relationship.

Rudy’s teacher Mr. Martinez discussed the Martian atmosphere.

(RELATIONSHIP: Mr. Martinez is the teacher of Rudy.)

Inez could see Mars through her father’s telescope.

(The telescope belongs to her father: OWNERSHIP)

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When/Why are possessive used?

Possessive nouns are used in place of longer phrases to make your writing less wordy and easier to understand.

We saw photos of the moons belonging to Mars. (wordy)

We saw photos of Mars’s moons. (easier to understand)

I went to the house of Maria to hang out. (wordy)

I went to Maria’s house to hang out. (easier to understand)

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Check for Understanding

Improve these sentences by rewording them with possessive nouns.

I can’t remember where I put the book of my teacher.
The outfit of my friend looks good on her.
The 50-yard dash of the men is my favorite track event.

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Correct Spelling of Singular Possessive Nouns

To make a singular noun possessive, simply add an apostrophe and –s.

Note: The rule is applied to all singular nouns, even if they already end in –s.

Singular Noun	Rule	Singular Possessive Noun	Shows relationship or possession
Mars	Add an apostrophe and –s	Mars’s	Scientists studied Mars’s atmosphere.
planet	Add an apostrophe and –s	planet’s	They noticed the planet’s color.
space craft	Add an apostrophe and –s	space craft’s	The space craft’s design was complicated.

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Check for Understanding

What is the possessive form of the singular noun in parentheses?

(Astronomy) history dates back 5,000 years to Babylon.
The Greek philosopher Aristotle claimed that Earth was the (solar system) center.
It was (Cylus) dream to become an astronaut.

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Correct Spelling of Regular Plural Possessive Nouns

To form a possessive noun from a regular plural noun ending in –s, just add an apostrophe.

Plural Noun Ending in -s	Rule	Plural Possessive Noun	Shows relationship or possession
moons	Add an apostrophe	moons’	Scientists studied all the moons’ different shapes.
rocks	Add an apostrophe	rocks’	They examined the rocks’ similarities and differences.
rocket engines	Add an apostrophe	rocket engines’	Several different rocket engines’ designs were compared.

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Check for Understanding

The (Babylonians) calendar was based on their observations of the stars and planets.
All of the (planets) orbits are actually centered around the sun.
Most of the (students) projects were excellent.

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Correct Spelling of Irregular Plural Possessive Nouns

To form a possessive noun from an irregular plural noun that does NOT end in –s, add an apostrophe and an –s.

Plural Noun not Ending in -s	Rule	Plural Possessive Noun	Shows Relationship or Possession
women	Add an apostrophe and -s	women’s	Some women’s careers are in the field of aerospace.
teeth	Add an apostrophe and -s	teeth’s	His teeth’s enamel was damaged by eating sugar.
people	Add an apostrophe and –s	people’s	People’s knowledge about outer space has improved.

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Check for Understanding

Some ancient people believed that (men) and (women) lives were governed by the stars.
Some popular (children) stories are about life on distant planets.
Several (people) opinions changed after the debate.

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Common Errors

Be sure not to make spelling errors by putting apostrophes in the wrong places.

Add an apostrophe and –s to show possession. Do NOT add an apostrophe and –s to form plural nouns.

I had six T-shirts in my drawer. (correct)

I had six T-shirt’s in my drawer. (incorrect)

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Why It Matters in Writing

Possessive nouns can make your writing less wordy and easier to understand. Be sure not to make spelling errors by putting apostrophes in the wrong places.


A radio show about a Martian landing grabbed the attention of the nation in 1938. Listeners of the show, believing the invasion was real, panicked.	A radio show about a Martian landing grabbed the nation’s attention in 1938. The show’s listeners, believing the invasion was real, panicked.

Wordy phrases

Possessive nouns