Their shows possession (their car), there points to a place or says that something exists (there it is; there is a problem), and they're is simply the short form of they are (they're late). The quickest test: if you can replace the word with "they are," use they're; if it answers the question "whose?", use their; if neither fits, the answer is there.
- their — belonging to them (possessive): Their flight was delayed.
- there — a place, or "something exists": Wait there. There are two options.
- they're — a contraction of "they are": They're on their way there.
These three words are homophones: they sound identical but mean completely different things. That is the only reason they get muddled — and it is why a spellchecker will not rescue you, because all three are correctly spelled words. Only a reading eye catches the wrong one.
Their: the possessive one
Their is the possessive form of they. It shows that something belongs to a group or, increasingly, to a single person. It sits right beside my, your, our and its, and it almost always comes before a noun: their house, their decision, their mistake.
Do not confuse it with theirs, which is a possessive pronoun that stands alone with no noun after it: The blue car is theirs. Both show ownership, but their needs a noun and theirs does not.
- ✓ The students handed in their essays.
- ✓ Everyone deserves their moment.
- ✗ The children lost there tickets. → ✓ The children lost their tickets.
There: place and existence
There does two jobs. First, it points to a place — it is the opposite of here, and it literally contains the word here: Put it over there. We drove there last summer. Second, it introduces the idea that something exists, usually in the phrases there is, there are, there was and there seems to be: There is a message for you. There are three reasons.
The contraction there's means "there is" or "there has" — never "belonging to them": There's a spider in the bath. There's been a mistake.
You will also meet there in fixed expressions like there you go, there, there (said to comfort someone) and been there, done that. These all trace back to the idea of place or existence, so the spelling stays there.
- ✓ Your keys are over there.
- ✓ There is no easy answer. (existence)
- ✗ Sit their and wait. → ✓ Sit there and wait.
They're: only ever "they are"
They're is a contraction of they are, and nothing else. The apostrophe stands in for the missing letter "a" in are. Before you write they're, expand it in your head: if "they are" makes sense in the sentence, you are right; if it sounds wrong, you need their or there instead.
- ✓ They're almost finished. — "they are almost finished" works.
- ✓ I think they're lost. — "I think they are lost" works.
- ✗ Their going to be late. → ✓ They're going to be late.
Correct vs incorrect: side by side
Almost every mistake with these words is a slip of the fingers, not a misunderstanding. Here are the classic errors and their fixes:
- ✗ Their over there with their friends. → ✓ They're over there with their friends.
- ✗ The keys are over their. → ✓ The keys are over there.
- ✗ They left they're coats behind. → ✓ They left their coats behind.
- ✗ There parents are away this week. → ✓ Their parents are away this week.
- ✗ I think there ready now. → ✓ I think they're ready now.
- ✗ Is it there problem or ours? → ✓ Is it their problem or ours?
The first line is the sentence that trips everyone up, because it uses all three in a row. Read it out slowly — "they are over there with the friends that belong to them" — and each choice becomes obvious.
Tricky cases and exceptions
There's vs theirs
There's means "there is" or "there has." Theirs is a thing belonging to them. Note that theirs never takes an apostrophe, even though it shows possession — just like ours, yours and hers: That table is theirs, but there's a chair missing.
Singular "their" is not an error
You will sometimes be told that their can only be plural, so "Someone left their bag" must be wrong. That is a myth. Singular their — used for one person of unknown or unspecified gender — has appeared in English for more than 600 years, in Chaucer, Shakespeare and Jane Austen, and it is now accepted by Merriam-Webster and by both the AP and Chicago style guides. Everybody grabbed their coat is perfectly correct.
"There is" with a plural noun
In careful writing, match there is/are to the noun that follows: There are three options, not There is three options. In everyday speech people constantly say there's before plurals ("there's loads of people"), which is fine when talking — but tighten it in formal writing.
"Theirselves" is not a word
Because their is so common, some people stretch it into theirself or theirselves. Standard English uses themselves (and, for a single person, themself is now accepted too): They fixed it themselves, never theirselves.
Is starting a sentence with "There is/are" wrong?
No. Some editors discourage it because it can be wordy — There are many people who disagree trims neatly to Many people disagree — but that is a style tip, not a grammar rule. There is and there are are correct, and often the most natural way to say that something exists.
A memory trick that actually works
Look inside each word:
- t-h-e-r-e contains here — both are about place. Here, there and where are all location words.
- t-h-e-i-r contains heir — an heir owns and inherits things, so their is about ownership.
- they're has an apostrophe where the "a" of are used to be, so it can only ever mean they are.
US vs UK: any difference?
None at all. This is one corner of English where American and British usage agree completely — same spellings, same meanings, same rules, and the same tendency to mix them up. There is no British "theyre" or American "thier"; the errors and the fixes are identical on both sides of the Atlantic. Both varieties now accept singular their, and both slip into there's before plurals in casual speech.
