Their or Thier: Which Is Correct?

Updated 2026-10-12 · Which One Is Correct editorial team

Quick answer: When writing in English, you must choose the correct spelling for the possessive pronoun. The word their is the right form, while thier is a common mistake. This guide explains the difference and helps you avoid confusion.

The Short Answer

The correct spelling is their, while thier is a misspelling. This distinction is vital for clear and professional communication.

People often confuse these words because they sound exactly the same. Many also mix up the rule about i before e, thinking thier follows a pattern that does not exist in this specific word.

Side-by-Side Comparison

Form	Status	Use it when
their	correct	use when showing joint possession or belonging
thier	incorrect	avoid this spelling in all formal writing
their	possessive adjective	use before nouns to indicate ownership
they	pronoun	use as the subject of a sentence

Correct Example Sentences

The students forgot to bring their notebooks to the library today.
Please make sure everyone brings their own water bottle to the hike.
The team celebrated their victory with a big party last night.
Do not forget to take your medicine after you eat your meal.
Each child must leave their toys on the shelf when they leave the room.
The dogs wagged their tails when they saw their owners walking home.
You should always respect your parents and their wishes.
The neighbors invited us over to see their new house this weekend.
It is important to wash your hands and keep them clean for your health.
The birds built their nests high up in the tall oak tree.
We need to check their seats to ensure everyone has a ride today.
The company praised their employees for their hard work and dedication.
Everyone needs to wear their seatbelt while driving in the car.

Common Mistakes and Fixes

Thier is a frequent typo that slips into informal emails when people rush.: their is the proper spelling used to show possession for a group.
A careless writer might type thier while describing shared belongings.: Correct usage requires their before the nouns that belong to them.
Remember the rule i before e except after c does not apply here.: Keep in mind that their follows the standard spelling without the extra r.
Students often see thier in online articles and assume it is valid.: Always verify that the text uses their since thier is never correct.
Using thier instead of their can make your writing look unprofessional.: Fix the error by swapping thier for their in every sentence.
The word thier appears often because keyboards make the error easy.: Take care to type the r after the i to form the correct word their.
Editors remove thier from drafts before publishing the final version.: Proofreading helps catch the mistake and replace it with their quickly.
Learning that thier is wrong helps you avoid embarrassment later.: Mastering the correct form their ensures your messages are clear.
Confusion about spelling often leads to thier appearing in student papers.: Study the spelling of their to prevent this common error from recurring.