Relative Pronouns
Learn how who, whom, whose, which and that connect a describing clause to a noun.
Who, whom, whose, which, that
A relative pronoun links extra information to a noun.
A relative pronoun introduces a clause that adds more information about a noun that came just before it. The clause it introduces is called a relative clause.
In the sentence The woman who called earlier left a message., the word who introduces the clause who called earlier, which describes the woman.
Relative pronouns use the same words as interrogative pronouns, but they serve a different purpose: connecting information rather than asking a question.
Before you begin
Relative pronouns share their forms with interrogative pronouns.
Words such as who, whose and which are used both to ask questions and to introduce relative clauses. Reviewing interrogative pronouns first can help make the difference clear.
The central idea
A relative pronoun connects a clause to the noun before it.
Compare two separate sentences with one sentence joined by a relative pronoun.
01
Two Separate Sentences
I have a neighbour. My neighbour grows amazing tomatoes.
02
Joined with a Relative Pronoun
I have a neighbour who grows amazing tomatoes.
The useful question is: What noun is this clause describing?
A relative pronoun always points back to a specific noun that appears immediately before it in the sentence.
The relative pronoun forms
Different relative pronouns are used for people and for things.
Who and whom for people
The man who answered the phone was very polite.
The man whom I spoke to was very polite.
Who introduces a clause where the person is the subject. Whom introduces a clause where the person is the object, though many speakers use who for both in everyday conversation.
Whose for ownership
The author whose book won the award gave a speech.
Whose shows that something belongs to the person or thing being described.
Which for things
The restaurant which opened last month is already popular.
Which is used for things, animals and ideas, not for people.
That for people or things
The book that I read last week was excellent.
The person that called earlier didn’t leave a name.
That can refer to either people or things, particularly in less formal writing and speech.
Defining and non-defining clauses
Some relative clauses identify the noun. Others simply add extra detail.
01
Defining Clause
Identifies exactly which noun is meant. No commas are used.
The students who arrived late missed the introduction.
02
Non-Defining Clause
Adds extra information about a noun already identified. Commas are used.
My brother, who lives in Chicago, is visiting next week.
The useful question is: Could the clause be removed without losing the identity of the noun?
In the defining example, removing the clause would leave it unclear which students are meant. In the non-defining example, the speaker’s brother is already identified; the clause simply adds detail.
That is generally used only in defining clauses, not in non-defining ones.
Omitting the relative pronoun
Some relative pronouns can be left out entirely.
When the relative pronoun is the object of the clause
The book that I read last week was excellent.
The book I read last week was excellent.
Both sentences are correct. In a defining clause, the relative pronoun can be dropped when it stands for the object of the clause.
When the relative pronoun is the subject
The man who answered the phone was very polite.
Here, who is the subject of the clause, so it cannot be removed.
A useful decision guide
Ask who or what the clause is describing, and how.
01
Is the noun a person?
Use who, whom or that.
02
Is the noun a thing?
Use which or that.
03
Does the clause identify the noun, or just add detail?
Identifying clauses use no commas; extra-detail clauses are set off with commas and do not use that.
04
Is the relative pronoun the object of its own clause?
In a defining clause, it can usually be left out.
Common mistakes
Match the relative pronoun to the noun and the type of clause.
Using which for a person.
Not: The teacher which helped me was very patient.
Correct: The teacher who helped me was very patient.
Which refers to things, not people.
Leaving out commas around a non-defining clause.
Not: My sister who lives in Berlin is a doctor. (if you have only one sister)
Correct: My sister, who lives in Berlin, is a doctor.
Without commas, the sentence suggests you have more than one sister and are identifying a particular one.
Using that in a non-defining clause.
Not: My car, that is red, needs washing.
Correct: My car, which is red, needs washing.
That is generally reserved for defining clauses.
Check your understanding
Which relative pronoun fits?
Choose the correct answer for each sentence.
The engineer __________ designed the bridge won an award.
✅ Exactly! The clause describes a person, the engineer.
❎ Not quite. Check whether the noun being described is a person or a thing.
Which noun does this clause describe?
The bridge, __________ took three years to build, opened yesterday.
✅ Exactly! With commas around the clause, this is non-defining, so which fits, not that.
❎ Not quite. Notice the commas around the clause.
The author __________ novel won the prize gave a short speech.
✅ Exactly! Whose shows that the novel belongs to the author.
❎ Not quite. Think about what shows ownership of the novel.
The film __________ we watched last night was excellent. (the relative pronoun is the object of the clause)
✅ Exactly! Since that or which would be the object of watched, it can be dropped in this defining clause.
❎ Not quite. Check whether the relative pronoun is the subject or the object of the clause.
Choose the best explanation
Select the sentence that explains the relative pronoun correctly.
Why does “My sister, who lives in Berlin, is a doctor” use commas?
✅ Exactly! With only one sister, the clause is non-defining and needs commas.
❎ Not quite. Think about whether the clause is needed to identify which sister is meant.
Why can “that” be dropped in “The book (that) I read was excellent”?
✅ Exactly! An object relative pronoun in a defining clause can usually be omitted.
❎ Not quite. Consider whether that is the subject or the object of the verb read.
Which sentence correctly uses a relative pronoun for a thing?
✅ Exactly! Which correctly refers to the restaurant, a thing.
❎ Not quite. Match each relative pronoun to whether it refers to a person or a thing.
Try it another way
Complete the sentence with the correct relative pronoun.
Type who, whose, which or that.
✅ Exactly! The clause describes a person, the doctor.
❎ Not quite. This clause describes a person.
✅ Exactly! Whose shows that the profits belong to the company.
❎ Not quite. Think about what shows ownership of the profits.
✅ Exactly! The clause describes a thing, the laptop.
❎ Not quite. This clause describes a thing, not a person.
Edit the sentence
Rewrite each sentence with the correct relative pronoun or punctuation.
The teacher which helped me was very patient. (correct the pronoun)
✅ Exactly! Who is used for people, not which.
❎ Not quite. Replace which with the relative pronoun used for people.
My car, that is red, needs washing. (correct the pronoun)
✅ Exactly! That is not generally used in a non-defining clause set off by commas.
❎ Not quite. This clause is set off by commas, so that should be replaced.
My brother who lives in Chicago is visiting next week. (add the missing commas, assuming you have only one brother)
✅ Exactly! With only one brother, the clause simply adds detail and needs commas.
❎ Not quite. Add commas before and after the clause about Chicago.
Quick review
A relative pronoun connects extra information to the noun before it.
Relative pronouns — who, whom, whose, which, that — introduce a clause describing a noun that came just before them.
Who, whom and whose refer to people; which refers to things; that can refer to either.
A defining clause identifies which noun is meant and uses no commas; a non-defining clause adds extra detail and is set off with commas.
That is generally used only in defining clauses.
When the relative pronoun is the object of a defining clause, it can often be left out.
Remember
Ask what the clause is describing, and whether it is needed to identify the noun.
A person or a thing decides the pronoun. Whether the clause identifies the noun or simply adds detail decides the punctuation, and sometimes whether the pronoun is needed at all.