What is it?
Relative clauses are dependent clauses that describe or identify a noun. They are introduced by relative pronouns: who (people), which (things), that (people or things in defining clauses), where (places), whose (possession). They come in two types: defining (no commas, essential information) and non-defining (with commas, additional information).
Why it matters for IELTS
Using complex sentences with relative clauses is a key marker of Band 7+ grammar. Simple sentences with no subordinate clauses limit your score to Band 5.
Common mistakes — corrected
People live in cities. They face more pollution.
People who live in cities face more pollution.
Combine two sentences with a relative clause to show grammatical complexity.
The policy which it was introduced in 2020 failed.
The policy which was introduced in 2020 failed.
Do not repeat the subject pronoun ("it") inside the relative clause.
My hometown, that is located in the south, is famous for its food.
My hometown, which is located in the south, is famous for its food.
In non-defining clauses (with commas), use "which" not "that".
IELTS tips
- →
Use "whose" to avoid awkward possessives: "Students whose parents are educated tend to perform better" — more natural than "Students with educated parents".
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Reduced relative clauses show higher range: "The policy introduced in 2020" = "The policy which was introduced in 2020".
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Non-defining relative clauses add sophistication to Task 2: "Globalisation, which has accelerated dramatically since the 1990s, has transformed employment patterns."
Frequently asked questions
What is the difference between "which" and "that" in IELTS?
In defining relative clauses (no commas), both "which" and "that" are acceptable. In non-defining relative clauses (with commas), only "which" is correct. In academic writing, "which" is generally preferred for things.
Do relative clauses improve my IELTS band score?
Yes. Using a variety of complex sentence types — including relative clauses — is necessary to achieve Band 7 or higher in Grammatical Range & Accuracy. A response with only simple sentences cannot score above Band 5 in this criterion.
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