Noun Clauses (Structure, Rules and Examples)

What Is a Noun Clause?

A noun clause is a dependent clause that functions as a noun. A sentence does not always use a single word as its subject, object, or complement.

Consider these two sentences:

Noun Phrase:

“I know the answer.”

In the first sentence, the answer is a noun phrase.

Noun Clause:

“I know what the answer is.”

In the second, what the answer is performs the same grammatical job.

That larger group of words is a noun clause.

How Noun Clauses Start

Noun clauses look like questions because they often begin with words such as:

what who where when why how

They may also begin with:

that whether if

But inside a sentence, they do not behave like ordinary questions. They function as nouns.

Internal Structure of a Noun Clause

Like other clauses, it contains its own subject and verb:

“I remember what she said.”

The noun clause is: what she said

• she = subject
• said = verb

The entire clause functions as the object of remember.

The Substitution Test

You can replace it with a simple noun or pronoun:

“I remember it.”

That substitution gives us a useful clue that what she said is working as a noun.

✨ Quick Challenge

Three of these four sentences contain a noun clause (can be substituted with “it” or “something”). One contains an adverbial clause telling when. Tap the sentence that doesn’t belong.

See the full answer

Answer: “We left the theater when the movie ended.”

A noun clause acts as a noun within the sentence and can typically be replaced with the pronoun it or something:

“I believe what she said.” ➔ I believe it. (Direct Object)
“Nobody knows where he went.” ➔ Nobody knows it. (Direct Object)
“She understands that honesty is important.” ➔ She understands it. (Direct Object)

In contrast, in “We left the theater when the movie ended,” the clause when the movie ended modifies the verb left by specifying when the action took place, making it an adverbial clause of time.

A Noun Clause Is Not Just Any Group of Words

A phrase can act like a noun, but it is not necessarily a noun clause. Compare:

“after the meeting”
This is a phrase.

“what happened after the meeting”
This is a clause because it contains a subject-verb structure.

The important difference is that a noun clause contains its own clause structure.

Example	Type	Reason
the old house	Noun phrase	No separate subject-verb structure
after lunch	Prepositional phrase	No clause
what she wanted	Noun clause	Contains subject and verb
where they live	Noun clause	Contains subject and verb
to finish the work	Infinitive phrase	Not a noun clause
that he was late	Noun clause	Contains subject and verb

Where Can a Noun Clause Appear?

A noun clause can occupy several positions in a sentence because nouns themselves have several grammatical roles. The most important ones are:

📌 Subject

📌 Direct Object

📌 Indirect Object

📌 Object of a Preposition

📌 Subject Complement

📌 Complement After Adjectives

Noun Clause as the Subject

A noun clause can come at the beginning of a sentence and act as its subject:

“What you said hurt my feelings.”

• What hurt my feelings? ➔ What you said.
• The entire clause is the subject.

Another example:

“Why she left remains a mystery.”

The noun clause why she left is the subject of remains.

More Examples

Where we stay is not important.
How the machine works is difficult to explain.
Who will lead the team has not been decided.

The subject can therefore be much longer than a single noun.

Why Subject Noun Clauses Can Feel Difficult

A sentence such as:

“What the manager decided was unexpected.”

may initially confuse learners because the sentence begins with what. They may think the sentence is asking a question. It is not.

The clause what the manager decided is the subject. The sentence means:

“The thing that the manager decided was unexpected.”

Useful Strategy:

A useful habit is to temporarily replace the noun clause with something:

“Something was unexpected.”

The sentence still has the same basic structure.

Noun Clause as a Direct Object

This is one of the most common uses:

“I know what you mean.”

• The verb is know.
• Know what? ➔ what you mean
• The noun clause is the direct object.

More Examples:

We discovered where the keys were hidden.
She explained why the schedule had changed.
They remember what happened that evening.
I don’t understand how this device works.

In each sentence, the noun clause answers the question what?

The Hidden Question Trick

Here is an easy way to avoid mistakes. Start with the direct question:

“Where is Sara?”

Now ask yourself: What do I want to say about this question?

You might write:

“I don’t know where Sara is.”

• Direct question: Where is Sara?

• Noun clause: where Sara is

The subject comes before the verb.

Direct question: “What did Tom buy?”

➔ Becomes: “I wonder what Tom bought.”

Direct question: “When will they arrive?”

➔ Becomes: “Nobody knows when they will arrive.”

“Whether” and “If” in Noun Clauses

Use whether or if when the noun clause expresses uncertainty or an alternative:

I don’t know whether she will attend.
I don’t know if she will attend.

Both are common in many situations. However, whether is often the better choice in formal writing and is necessary in some structures, especially when alternatives are explicitly presented:

We need to decide whether to stay or leave.
The question is whether the plan will work.

A useful rule: Use “whether” when the sentence presents a choice, alternative, or formal uncertainty.

“Whether” vs. “If”

Although they can overlap, they are not completely interchangeable:

Situation	Better Choice
Everyday uncertainty	if / whether
Formal writing	whether is often preferred
“or not” immediately after the word	whether
Before an infinitive	whether
Explicit alternatives	whether
After a preposition	whether

Examples:

We are unsure whether to leave now.
It depends on whether they agree.
I don’t know whether or not he will come.

In these cases, whether is the natural choice.

Noun Clauses With “Who,” “Whom,” and “Whoever”

These forms can cause confusion because the clause itself can have a grammatical role while the opening word has another role inside the clause. Consider:

“I don’t know who called.”

Here, who is the subject of called.

Now:

“I don’t know whom she called.”

Here, she is the subject and whom is the object of called.

Compare

Sentence	Role of the WH-word
I know who called.	Subject
I know whom she called.	Object
Ask who wants coffee.	Subject
Ask whom they invited.	Object

In everyday English, who is widely used in places where traditional formal grammar would use whom. In formal writing, however, the distinction can still matter.

“Whoever,” “Whatever,” and Other -Ever Words

Noun clauses can also begin with words ending in -ever. Common examples include:

whoever whatever whichever wherever whenever however

For example:

Whoever finishes first can leave.
Choose whatever you like.
I’ll support whichever option you choose.
Whatever happens will be dealt with later.

These words often carry a meaning such as any person who, anything that, or any choice that.

✨ Quick Challenge

Which of the following sentences correctly converts the direct question “Where did she go?” into an embedded noun clause with standard statement word order? Tap your answer.

See the full answer

Answer: “Nobody knows where she went.”

When turning a direct question into an embedded noun clause:

Drop the dummy auxiliary verb did.
Use standard statement word order: WH-word + Subject + Verb (where + she + went).
❌ “Nobody knows where did she go.” (Question order error)
✅ “Nobody knows where she went.” (Correct noun clause)

Noun Clauses in Academic and Formal Writing

Noun clauses are particularly useful when discussing:

claims evidence findings opinions explanations causes decisions questions assumptions conclusions

Examples:

Researchers examined whether the treatment was effective.
The results show that the method can reduce errors.
It remains unclear why the results differed.
What the study reveals is important for future research.

These structures allow complex ideas to fit naturally into a sentence without turning every thought into a separate sentence.

A Practical Noun Clause Pattern Chart

Function	Common Pattern	Example
Subject	Noun clause + verb	What she decided surprised us.
Direct object	Subject + verb + noun clause	I know what she decided.
Indirect object	Subject + verb + person noun clause + object	Give whoever needs one a copy.
Object of preposition	Subject + verb + preposition + noun clause	We talked about what happened.
Subject complement	Subject + linking verb + noun clause	The problem is that we are late.
Adjective complement	Subject + be + adjective + noun clause	I am glad that you came.

Noun Clause Examples at a Glance

Here are examples of the major patterns in one place:

• “What he said was unexpected.” ➔ Subject

• “I remember what he said.” ➔ Direct object

• “We argued about what he said.” ➔ Object of a preposition

• “The truth is that he was mistaken.” ➔ Subject complement

• “I am certain that he was mistaken.” ➔ Adjective complement

• “Give the prize to whoever finishes first.” ➔ Object of a preposition

Seeing the same type of clause in different positions makes the concept much easier to recognize.

Practice Exercises

Practice: Identify the Noun Clause

Find the noun clause in each sentence:

What you choose is entirely up to you.
I don’t remember where I put the documents.
She explained why the machine stopped.
We are uncertain about whether the plan will work.
Whoever solves the puzzle will receive a prize.
The question is whether they will agree.
Tell me what you saw.
I am pleased that you enjoyed the lesson.

No.	Noun Clause	Function
1	What you choose	Subject
2	where I put the documents	Direct object
3	why the machine stopped	Direct object
4	whether the plan will work	Object of preposition
5	Whoever solves the puzzle	Subject
6	whether they will agree	Subject complement
7	what you saw	Direct object
8	that you enjoyed the lesson	Adjective complement

Practice: Correct the Noun Clauses

Correct each sentence below:

1. ❌ Incorrect: “I don’t know where does she live.”

✅ Correct: “I don’t know where she lives.”

2. ❌ Incorrect: “She believes, that he is honest.”

✅ Correct: “She believes that he is honest.”

3. ❌ Incorrect: “Why he left still unclear.”

✅ Correct: “Why he left is still unclear.”

4. ❌ Incorrect: “Tell me what did you see.”

✅ Correct: “Tell me what you saw.”

5. ❌ Incorrect: “We discussed about what happened.”

✅ Correct: “We discussed what happened.”

Note: The verb discuss normally does not need about.

Practice: Noun Clause or Relative Clause?

Identify the type of clause in each sentence:

I know what she bought.
The dress that she bought is expensive.
Tell me where they live.
The house where they live is very old.
Nobody knows who broke the window.
The boy who broke the window apologized.

No.	Type	Why?
1	Noun clause	It is the object of know
2	Relative clause	It describes dress
3	Noun clause	It is the object of tell
4	Relative clause	It describes house
5	Noun clause	It is the object of knows
6	Relative clause	It describes boy

This is an excellent distinction to master because the same introductory word can appear in both structures.

Frequently Asked Questions About Noun Clauses

What is a noun clause in simple words?

A noun clause is a group of words containing a subject and verb that performs the job of a noun.

Is a noun clause dependent or independent?

A noun clause is normally a dependent clause. It functions as a noun but cannot normally stand alone as a complete sentence.

What are the common noun-clause starters?

Common starters include that, what, who, whom, whose, which, when, where, why, how, whether, if, whoever, whatever, and whichever.

Can a noun clause be the subject?

Yes.

“What she said was true.”

Here, the entire clause is the subject.

Can a noun clause be an object?

Yes. This is one of its most common functions:

“I know what she said.”

Do noun clauses need commas?

Usually not. A noun clause normally fits directly into the grammatical structure of the sentence without being separated by commas.

Can “that” be omitted from a noun clause?

Yes, in many cases when that introduces an object noun clause:

• “I think that he is right.”
• “I think he is right.”

What is the difference between a noun clause and an adjective clause?

A noun clause takes the place of a noun. An adjective or relative clause describes a noun that is already present in the sentence.

What is the difference between a noun clause and an adverb clause?

A noun clause performs a noun’s grammatical role (subject, object, complement). An adverb clause modifies another part of the sentence by expressing information such as time, reason, condition, or contrast.

Is “what she said” always a noun clause?

No. Its function must be examined in context. In “I remember what she said,” it functions as a noun clause. The important point is always the clause’s job in the sentence.

Why is “I don’t know where is he” incorrect?

Because the clause is an embedded question, not a direct question. Use statement word order:

✅ Correct: “I don’t know where he is.”

Can noun clauses begin a sentence?

Yes.

“What you decide is your responsibility.”

When a noun clause is the subject, you normally do not place a comma between it and the predicate.

Noun Clause: Quick Reference

Question	Answer
What is it?	A dependent clause functioning as a noun
What does it contain?	Its own subject and verb
Can it be a subject?	Yes
Can it be a direct object?	Yes
Can it be an indirect object?	Yes
Can it follow a preposition?	Yes
Can it be a subject complement?	Yes
Common starters	that, what, who, where, when, why, how, whether, if
Does it normally stand alone?	No
Does it normally need commas?	No
Does an embedded question use question word order?	No
Can “that” sometimes be omitted?	Yes
Can it be confused with a relative clause?	Yes
Best identification method	Find its grammatical function

Noun Clauses (Structure, Rules and Examples)