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In my years of grading student papers, “thier” might be the single most common misspelling I mark. Here’s the trap: “thier” looks almost identical to “their,” it’s easy to type quickly, and spell-check sometimes lets it slip through. But here’s the truth: “thier” is not a word in English. It’s a misspelling. Full stop.
The real confusion isn’t about meaning — “their” is a possessive pronoun meaning “belonging to a group.” The confusion is simply spelling. I’ll show you why the misspelling happens, the one rule that makes “their” stick, how to spot and fix errors, and practice examples that cement it in your memory.
Key Takeaways
- “Their” is correct; “thier” is not a word — always use “their” for the possessive pronoun.
- The mnemonic: “HEIr in THEIr” — both contain “HEI” to help you spell it right.
- Three homophones to keep straight — “their” (possession), “there” (location), “they’re” (contraction of “they are”).
- Common mistake — typing too fast and swapping the “ei” to “ie” creates the misspelling.
- Quick test — if you can swap it with “of theirs” or “belonging to them,” use “their”.
The Correct Spelling: “Their”
Definition of “Their”
“Their” is a possessive pronoun that shows something belongs to a group of people. It’s always spelled with an “e” before the “i”: T-H-E-I-R. When you see this word, it means “belonging to them.”
Example 1: The students remembered to bring their textbooks to class.
Example 2: The athletes put on their uniforms before the game.
Example 3: Their house has a beautiful garden in the backyard.
Why “Thier” Is Wrong
“Thier” — with the “i” before the “e” — is not a word in English. It’s a misspelling that happens because:
- Fast typing can swap the letters without you noticing
- It looks similar enough to pass a quick glance
- Some spell-checkers miss it if the document language setting is off
But no matter how common the mistake is, it’s still wrong. Always use “their.”
The “HEIr in THEIr” Memory Hook
Here’s a mnemonic that sticks: Both words contain the letters “H-E-I” in sequence:
- HEIr — a person who inherits something
- THEIr — possessive pronoun, “belonging to them”
If you can remember “heir” (the person who gets the inheritance), you’ll always spell “their” correctly because they share the same “HEI” sequence.
The Golden Rule: There is no word “thier” in English. Always use “their” for the possessive pronoun. When in doubt, ask yourself: “Does this mean ‘belonging to them’?” If yes, use their (with the “e” before “i”).
Three Confusing Words: “Their,” “There,” “They’re”
The real confusion often involves three homophones (words that sound the same). Let me separate them clearly:
Their (Possessive Pronoun)
“Their” = belonging to a group of people. Swap test: can you replace it with “of theirs”? If yes, use “their.”
Example 1: Their car is parked outside. (= The car of theirs is parked outside. ✓)
Example 2: The team celebrated their victory. (= The team celebrated the victory of theirs. ✓)
There (Location or Existence)
“There” = a place or to indicate something exists. It often follows “is,” “are,” “was,” “were.”
Example 1: The restaurant is over there. (location)
Example 2: There are three cats on the fence. (existence)
They’re (Contraction)
“They’re” = a contraction (short form) of “they are.” If you can say “they are” in the sentence, use “they’re.”
Example 1: They’re going to the beach this weekend. (= They are going…)
Example 2: They’re my best friends. (= They are my best friends…)
Quick Identification Table
| Word | Part of Speech | Meaning | Test / Swap |
|---|---|---|---|
| Their | Possessive pronoun | Belonging to them | Replace with “of theirs” or “belonging to them” |
| There | Adverb / Pronoun | A place or to show existence | Can you point to a location? Or does the sentence have “is/are”? |
| They’re | Contraction | They are | Say “they are” — does it fit? |
Common Mistakes and How to Fix Them
✗ Incorrect: Thier friends are coming to the party.
✓ Correct: Their friends are coming to the party.
Why: The friends belong to them — use “their” (possessive). “Thier” is not a word.
✗ Incorrect: Their going to the beach.
✓ Correct: They’re going to the beach.
Why: This means “they are going,” so use the contraction “they’re,” not “their.”
✗ Incorrect: Put your bags over their.
✓ Correct: Put your bags over there.
Why: “There” indicates a location (over there). Don’t confuse it with the possessive “their.”
Sample Dialogue
Jake: Is it “their” or “thier”? I always mix it up.
Sofia: “Their” — with an ‘e’ before the ‘i’. Think of “heir” — the person who inherits. Both have “HEI” in them.
Jake: So “thier” isn’t a word at all?
Sofia: Nope, it’s a misspelling. And the easiest way to remember is the swap test: if you can say “of theirs” in the sentence, use “their”.
Jake: “Their house is big” = “Of theirs house is big”? That sounds weird.
Sofia: Ha, yes, but the meaning is there. “The house of theirs is big.” It’s possessive, so “their” is right.
Quick Quiz
- Choose the correct word: “______ cat is very friendly.” (Their / There / They’re)
- Choose the correct word: “We left our jackets over ______.” (their / there / they’re)
- Choose the correct word: “______ coming to dinner tonight.” (Their / There / They’re)
- Is “thier” a word in English?
- Yes, it means the same as “their”
- No, it’s a misspelling
- Sometimes, in informal writing
- Which mnemonic helps you spell “their” correctly?
- “HEIr in THEIr” — both have HEI
- “TH” sounds like “th”
- It’s just a common word
Answers: 1. Their · 2. there · 3. They’re · 4. b (No, it’s a misspelling) · 5. a (“HEIr in THEIr”)
Related Articles
- ↑ Master Pillar: English Grammar
- Accept vs. Except — similar-sounding words
- ↑ Back to pillar: English Confused Words (Pillar)
Frequently Asked Questions
Is “thier” ever correct in English?
No. “Thier” is never correct. It’s always a misspelling of “their.” There is no context in which “thier” is the right word. Always use “their” (possessive pronoun), “there” (location), or “they’re” (contraction of “they are”).
What is the easiest way to remember the correct spelling of “their”?
Remember the word “heir” — a person who inherits something. Both “heir” and “their” contain the letters “HEI” in sequence. If you can spell “heir,” you can spell “their” by putting a “t” in front and an “r” at the end.
How do I know when to use “their” instead of “there” or “they’re”?
Use the swap test: (1) Can you replace it with “of theirs” or “belonging to them”? → use “their.” (2) Does it describe a location or follow “is/are”? → use “there.” (3) Can you say “they are”? → use “they’re.”
Can “their” be used with a singular noun?
Yes. Modern English increasingly uses “their” as a singular possessive pronoun to refer to one person of unknown or non-binary gender. Example: “A student left their backpack in the library.” This is now considered correct in most style guides, including AP and APA.
What are some common sentences using “their” correctly?
Here are examples: “The team celebrated their victory.” “Their house is near the park.” “The students submitted their essays on time.” “The athletes wore their uniforms.” “Their dog loves to play fetch.” In each case, “their” means “belonging to them.”
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