I'm note (not) sure

Writers often mix up their, they're, and there because the words sound the same. The specific error "Their going to" replaces the contraction they're (they are) with the possessive their, removing the verb and breaking the sentence.

Quick answer

Use they're (they are) when you mean "they are." Use their only to show possession. Unless "going to" is a noun owned by someone (very rare), "Their going to" is incorrect.

"They're going to" = they are going to (correct for future actions).
"Their" = possessive: their books, their plan.
"There" = place or a placeholder: put it there; there are many reasons.

Core explanation: why "Their going to" is wrong

"Their" is a possessive pronoun; "they're" is a contraction of "they are." Writing "their going to" removes the verb "are" and leaves a phrase that doesn't make grammatical sense in normal usage.

Check whether the sentence needs a verb (they are) or possession (their).
If you can substitute "they are" and the sentence still makes sense, use they're.
If the phrase shows ownership, use their.

Work - Wrong: Their going to submit the budget tomorrow.
Work - Right: They're going to submit the budget tomorrow.
School - Wrong: Their going to hand back the graded tests next week.
School - Right: They're going to hand back the graded tests next week.

Grammar: contractions, possession, and subject-verb clarity

Contractions replace a verb phrase: they're = they + are. Possessive pronouns (their, our, your) never include an apostrophe. If choosing "their" leaves you without a verb, it's likely the wrong word.

Test: expand the contraction. If "they are" fits, keep they're or write they are.
Do not use an apostrophe for possessive pronouns (their, our, your).
When unsure, write the full form: "They are going to..."

Usage: They're = they are → They're attending the meeting.
Usage: Their = possessive → Their agenda looked full.

Real usage and tone: where mistakes show and what they signal

Readers usually forgive small homophone errors in casual chats, but the same mistakes in emails, reports, or essays can look careless. Use "they are" in formal writing or "they're" for a conversational tone.

Avoid the error in emails, memos, and proposals.
In school work, instructors mark grammar mistakes-use the correct form.
In casual messages, clarity still matters: a quick check saves confusion.

Work - Wrong: Their going to lead the Q3 review - pls be on time.
Work - Right: They're going to lead the Q3 review - please be on time.
School - Wrong: Their going to fail the exam if they don't study.
School - Right: They're going to fail the exam if they don't study.
Casual - Wrong: Their going to crash the game night if we arrive late.
Casual - Right: They're going to crash game night if we arrive late.

Examples: ready-to-use sentences (work, school, casual)

Use these corrected lines directly. Each pair shows the common wrong form and the correct alternative; some include alternate rewrites for tone or clarity.

Work - Wrong: Their going to finish the client proposal by Friday.
Work - Right: They're going to finish the client proposal by Friday.
Work - Wrong: I think their going to ask for more time on the deliverable.
Work - Right: I think they're going to ask for more time on the deliverable.
School - Wrong: Their going to present their research in the seminar next week.
School - Right: They're going to present their research in the seminar next week.
School - Wrong: Their going to revise the essay tonight; can you review it tomorrow?
School - Right: They're going to revise the essay tonight; can you review it tomorrow?
Casual - Wrong: Their going to the concert - want to join?
Casual - Right: They're going to the concert - want to join?
Casual - Wrong: Their going to pick up pizza on the way over.
Casual - Right: They're going to pick up pizza on the way over.
Rewrite (more formal): They will submit the report by Friday.
Rewrite (active): The team plans to submit the report by Friday.
Rewrite (concise casual): Looks like they'll be late.

Try your own sentence

Test the whole sentence, not just the phrase. Context usually reveals whether the verb or possession is correct.

How to fix your own sentence: a quick editing checklist

Use this four-step check whenever their/they're/there feels uncertain: expand, test, replace, polish.

1) Expand: If you suspect a contraction, expand it. Does "they are" read naturally? If so, use they're.
2) Test grammar: After expanding, confirm the sentence has a clear verb. If not, you probably need their for possession or a different construction.
3) Replace and read aloud: Swap in they're or their and read it. Which one sounds right?
4) Polish: Choose "they are" for formality, "they're" for casual tone, and "their" only for ownership.

Example: "Their going to call" → expand to "They are going to call" → use "They're going to call."

Memory tricks and quick rules to stop the swap

Short mnemonics and a small habit reduce errors. Pause and expand to "they are" when in doubt; look for ownership for "their"; use "there" for places or existential phrases.

"They're" = try expanding to "they are." If it fits, keep it.
"Their" = ownership - does the noun belong to someone?
"There" = place or used with "to be" (there is/there are).

Mnemonic: their → heir → possession.

Hyphenation, spacing, and edge cases

Some errors come from typing, not grammar: "Theirgoing" or extra spaces can hide the real problem. Autocorrect sometimes swaps they're for their, so scan for odd spacing or joined words.

Rarely, a capitalized phrase like "Their Going-To" could be a proper name and therefore correct. In ordinary sentences, however, use they're for "they are."

Search for "their going" to spot likely slips.
Check for missing apostrophes or double spaces introduced by autocorrect.
If you see a capitalized phrase, confirm whether it's a proper noun before changing it.

Wrong: Theirgoing to be delayed due to traffic.
Right: They're going to be delayed due to traffic.

Similar mistakes to watch for

The same expand-and-test habit applies to other homophones: your/you're, its/it's, who's/whose. Expand contractions and check ownership whenever a pronoun looks suspicious.

your vs you're: "you're" = you are. Expand to check.
its vs it's: "it's" = it is; "its" shows possession.
who's vs whose: "who's" = who is; "whose" shows possession.

Wrong: Your going to love this chapter.
Right: You're going to love this chapter.
Wrong: Its a common mistake to mix up these words.
Right: It's a common mistake to mix up these words.

FAQ

Is "their going to" ever correct?

Almost never. "Their" is possessive, so "their going to" would only work if "going to" were a noun phrase owned by someone. For ordinary future meaning, use they're going to or they are going to.

Should I write "they're" or "they are" in a formal report?

Prefer "they are" in formal reports for clarity. Use "they're" in informal writing or when a conversational tone is appropriate.

How can I remember the difference between their, they're, and there?

Quick check: expand "they're" to "they are." If that fits, use they're. If the sentence shows ownership, use their. If it's about place or existence, use there.

My phone autocorrect keeps changing they're to their - how do I stop it?

Add correct phrases to your keyboard dictionary, reduce aggressive autocorrect, and make a habit of scanning pronouns before sending messages.

Is there a tool that catches "their going to" automatically?

Yes. Grammar checkers flag homophone errors and offer corrections. For a quick check, paste your sentence into a checker to see suggested fixes and brief explanations.

Want a second pair of eyes?

If homophone slips show up often in your drafts, a quick grammar check can save time and reduce small errors that undermine clarity. Paste a sentence or paragraph into a checker to get an instant correction and explanation for "their going to" versus "they're going to."