Theirs is the correct possessive pronoun, while their’s is always incorrect in standard English.
I still remember when I wrote their’s house in a blog and someone corrected me it felt embarrassing 😅. Many people search their’s or theirs because apostrophes in English are confusing, especially with possessive words.
This article will clear the confusion, explain the rules, and help you use theirs correctly in writing and speaking.
Their’s or Theirs : Quick Answer
Theirs = correct possessive pronoun (means something belongs to them).
Their’s = incorrect spelling (never used in proper English).
Examples:
- This book is theirs.
- The responsibility is theirs, not ours.
❌ Their’s car is parked outside.
✅ Their car is parked outside.
The Origin of Their’s and Theirs
The word their comes from Old Norse þeira, meaning “of them.”
Over time, English created possessive forms:
- their (possessive adjective)
- theirs (possessive pronoun)
Unlike many nouns, possessive pronouns do not use apostrophes.
That is why theirs, yours, hers, ours, its never take an apostrophe.
People mistakenly add ’s because they think it shows possession, but in pronouns, it does not work that way.
British English vs American English Spelling
There is no difference between British and American English for this word.
| Form | British English | American English | Meaning |
| their | ✔ | ✔ | possessive adjective |
| theirs | ✔ | ✔ | possessive pronoun |
| their’s | ✖ | ✖ | incorrect form |
Important: Both US and UK follow the same grammar rule.
Which Spelling Should You Use?
🇺🇸 For American audience
Always use theirs when something belongs to them.
🇬🇧 For UK/Commonwealth audience
Use theirs (same rule).
🌍 For global audience
Use theirs to sound professional and grammatically correct.
Never use their’s in formal or informal writing.
Common Mistakes with Their’s or Theirs
Typing Error
❌ Their’s house is beautiful.
✅ Their house is beautiful.
Using Apostrophe Incorrectly
❌ The car is their’s.
✅ The car is theirs.
Confusing Their and Theirs
❌ This is their.
✅ This is theirs.
Thinking ’s Always Means Possession
❌ The decision is their’s.
✅ The decision is theirs.
Copying Incorrect Online Usage
❌ Many blogs use their’s incorrectly.
✅ Good writers always use theirs.
Theirs or Their’s in Everyday Examples
📧 Emails
- This project is theirs, not ours.
- The documents are theirs, so ask them.
📰 News
- The victory was theirs after a long struggle.
- The responsibility is theirs, officials said.
📱 Social Media
- The credit is theirs, not mine.
- That idea is theirs, and it’s amazing.
🧾 Formal Writing
- The final decision was theirs.
- The rights are theirs under the agreement.
Their’s or Theirs : Google Trends & Usage Data
People search their’s or theirs because:
- Apostrophe rules confuse learners
- Autocorrect sometimes suggests wrong forms
- Many social media posts use incorrect spelling
Search interest is high in:
- United States
- United Kingdom
- India
- Pakistan
- Australia
Common contexts:
- Academic writing
- Blogging and content creation
- Grammar learning
- School assignments
Professional writers always use theirs, while their’s is a common learner mistake.
Comparison Table: Their vs Theirs vs Their’s
| Word | Correct? | Type | Example |
| their | ✔ | possessive adjective | Their house is big |
| theirs | ✔ | possessive pronoun | The house is theirs |
| their’s | ✖ | incorrect | ❌ Their’s house |
FAQs About Their’s or Theirs
1. Is “their’s” ever correct?
No, their’s is never correct in standard English.
2. When should I use “theirs”?
Use theirs when you mean something belongs to them, without naming the object again.
3. What is the difference between their and theirs?
- Their = comes before a noun (their book).
- Theirs = replaces the noun (the book is theirs).
4. Why doesn’t “theirs” have an apostrophe?
Possessive pronouns do not use apostrophes in English grammar.
5. Is theirs singular or plural?
Theirs can refer to one or many people, depending on context.
6. Can I use theirs in formal writing?
Yes, it is correct in formal, academic, and professional writing.
7. Is theirs pronounced differently from their’s?
No, they sound the same, which causes confusion.
Conclusion
Understanding their’s or theirs is easy once you learn one simple rule: possessive pronouns never use apostrophes. The correct word is theirs, and their’s is always wrong. I used to make this mistake too, especially when writing quickly, but remembering that their shows ownership before a noun and theirs replaces the noun helped me fix it forever.
Using the correct form makes your writing clear, professional, and trustworthy. If you want to sound fluent and confident in English, always use theirs and avoid their’s completely. This small grammar rule can make a big difference in how polished your writing looks.
My name is Antonia White, and I’m an English writer who enjoys crafting thoughtful and engaging stories. I focus on clarity and depth in my writing, aiming to connect with readers through meaningful ideas and a genuine, approachable style.
