Possessive Nouns in English Grammar

Just here for the exercises? Click here.

What is a possessive noun?

A possessive noun is when we add apostrophe s (’s) (also: possessive s) or just an apostrophe (’) to a noun to show that it owns something. We can also indicate possession using the preposition of.

Learn when to use an apostrophe in English grammar, then put your knowledge to the test in the exercises.


Yasmin’s company publishes children’s books. She is head of the company.

It is a small company, but very international.

Officially, the company language is English, but they speak many different languages in the office.

Today, two students are starting an internship at Yasmin’s company.

The aim of the internship is to improve students’ language skills and give them work experience.

Yasmin shows the students the interns’ desk. It is at the back of the office.

Later, they will attend a meeting about this quarter’s sales numbers.

How to use the possessive s

The basic rule is as follows: use apostrophe s (’s) with singular nouns and just an apostrophe (’) with regular plural nouns.

the intern’s desk
the desk belongs to one intern
the interns’ desk
the desk belongs to more than one intern

The longer explanation is that the type of possessive depends on the final letter of the noun:

  • add ’s to all nouns that don’t end in -s; i.e. singular nouns and irregular plurals.
this quarter’s sales
singular noun
Yasmin’s company
singular noun
a children’s book
irregular plural noun
  • just add an apostrophe (’) to nouns that end in -s; i.e. regular plural nouns and some singular nouns.
students’ language skills
plural noun
James’ friend
singular noun ending in -s

Singular nouns ending in -s: apostrophe s or just apostrophe?

Singular nouns that end in -s can take just an apostrophe or ’s in the possessive, although the latter is less common.

James’ friend = James’s friend
the boss’ desk = the boss’s desk

If we are referring to two nouns, we add s to the final one.

Paola and Callum’s first day
not: Paola’s and Callum’s first day.

Possessive s: extra info

We also use the possessive s in the following situations:

  • with time periods
I have a week’s holiday to use.
All in a day’s work.
  • in short answers
Whose jacket is this?
It’s Carmen’s.
  • to refer to places we are familiar with (mostly in spoken language)
I was at the doctor’s yesterday.
I’m having dinner at Paul’s tonight.
Meet me at the hairdresser’s.

Possessive with of

Instead of ’s, we can also indicate possession with noun + of + noun, mostly when the noun is a non-living thing such as an organisation, company, country, etc.

the success of the company = the company’s success
the aim of the internship = the internship’s aim

As shown above, ’s and of are often interchangeable. However, there are some cases where only one is possible:

When to use of

We use of and not ’s when:

  • the noun phrase is very long
the head of one of the most successful publishing companies
not: one of the most successful publishing companies’ heads
  • with beginning, middle and end, as well as top, bottom, front, back, side, etc.
the end of the day
not: the day’s end
the back of the office
not: the office’s back
  • with words like sound, smell, taste, etc.
the sound of the waves and the smell of the sea
not: the waves’ sound and the sea’s smell
  • with official titles
the President of the United States
not: the United States’ President
  • we wish to sound more formal
the sales of this quarter
informal: this quarter’s sales

When not to use of

As a general rule, we don’t use of when the noun is a person or other living thing; we use ’s instead:

Yasmin’s company
not: the company of Yasmin
the interns’ desk
not: the desk of the interns

Sometimes we make an exception in formal language:

the works of Shakespeare


Sometimes we omit the possessive completely and indicate possession with noun + noun. This is only possible when referring to non-living things.

The company language is English.
not: the company’s language
The office culture is friendly.
not: the office’s culture