Theirs or Their’s:(Ultimate Guide to Correct Usage) of 2026

Many English learners and even native speakers get confused between “theirs” and “their’s”. It’s a common spelling mistake that can make your writing look unprofessional.

People often search for this keyword because they want a clear, quick answer about which form is correct and why. Understanding the difference improves emails, social media posts, essays, and professional writing.

The confusion mainly arises because “their” already ends in “r”, and adding an apostrophe feels natural to some writers.

However, apostrophes are not always needed, and using them incorrectly changes the meaning. This guide explains the correct usage, historical origin, British vs American spelling, and everyday examples.

By the end, you will confidently know when to use “theirs” and avoid errors like “their’s”.

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Theirs or Their’s – Quick Answer

Quick Answer: The correct form is “theirs”. “Their’s” is incorrect.

• Example 1: That book is theirs, not ours.
• Example 2: The decision was entirely theirs to make.

Tip: Use “theirs” whenever you want to show possession without an apostrophe.

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The Origin of Theirs or Their’s

The word “theirs” comes from Middle English “theres”, derived from the Old English pronoun “þāra” (meaning “of them”). Historically, English pronouns often did not require apostrophes to indicate possession, unlike contractions such as “it’s” for “it is”.

The mistaken use of “their’s” likely comes from overgeneralizing the apostrophe rule used in other possessive forms. English has inconsistent rules, and many learners apply apostrophes where they aren’t needed.

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British English vs American English Spelling

Form	British English	American English	Correct?
theirs	✔ Correct	✔ Correct	Always correct
their’s	✖ Incorrect	✖ Incorrect	Never correct

Both UK and US English agree that “theirs” is correct. Apostrophes are never added to this possessive pronoun.

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Which Spelling Should You Use?

No matter your audience US, UK, Commonwealth, or global the correct choice is always “theirs”. Avoid “their’s” completely; it is considered a spelling mistake in formal, academic, and professional writing.

• US audience: Use “theirs”.
• UK/Commonwealth audience: Use “theirs”.
• Global audience: Use “theirs”.

Pro Tip: Apostrophes are only for contractions (e.g., “it’s” = “it is”) or singular possessives (e.g., “the dog’s toy”).

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Common Mistakes with Theirs or Their’s

• ❌ Wrong: That car is their’s.
• ✅ Correct: That car is theirs.
• ❌ Wrong: The choice was their’s.
• ✅ Correct: The choice was theirs.

Remember: Apostrophes in possessive pronouns are always incorrect.

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Theirs or Their’s in Everyday Examples

• Emails: “The files on the drive are theirs.”
• Social media: “That meme is clearly theirs!”
• News articles: “The victory belonged to theirs, not theirs rivals.”
• Formal writing: “The policy changes are theirs to implement.”

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Theirs or Their’s – Google Trends & Usage Data

According to Google Trends, searches for “theirs or their’s” spike when students and writers double-check grammar rules. The keyword is popular in the US, UK, India, and Canada. Most users want a quick answer, showing this is a common point of confusion globally.

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Keyword Variations Comparison

Variation	Correct Usage	Notes
theirs	✔	Standard possessive pronoun
their’s	✖	Incorrect, should never be used
theirs’	✖	Incorrect, apostrophe not needed
there’s	✔	Contraction of “there is” (different meaning)

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FAQs

1. Is “their’s” ever correct?
No, “their’s” is always incorrect. Use “theirs”.

2. Can I use “theirs” for singular nouns?
No, “theirs” is plural. For singular, use “his”, “hers”, or “its”.

3. Why do people write “their’s”?
It’s a common mistake from overusing apostrophes in English.

4. Is “theirs” used in American and British English?
Yes, it is correct in all English varieties.

5. Can I use “their’s” in informal texting?
Even in texting, it’s better to use “theirs” to avoid confusion.

6. How do I remember the correct form?
Think: possessive pronouns never need apostrophes.

7. Is “theirs” pronounced differently than “their’s”?
Yes, only “theirs” is correct and has a single pronunciation: /ðɛərz/.

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Conclusion:

Mastering the difference between “theirs” and “their’s” is simple once you know the rule: never use an apostrophe for possessive pronouns.

This common mistake can reduce the credibility of your writing, but remembering the quick tip “theirs” is always correct prevents errors in emails, essays, social media posts, and professional documents.

Understanding its origin, British vs American conventions, and seeing everyday examples helps cement proper usage. Avoid “their’s”, and you’ll always appear confident and knowledgeable in written English.

With consistent practice, the correct usage becomes second nature, ensuring your writing is clear, professional, and error-free.For academic work, online communication, or formal publications, stick with “theirs”.

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