There is a difference between Their and They're. While "their" means belonging to them, they're is a contraction which stands for "they are".
|Used as a contraction||No||Yes - they're is an abbreviation for "they are"|
|Meaning||Belonging to them||They are|
- She was envious of their expensive shoes.
- It's time to go. They're here to pick us up.
- They're claiming to do everything they can to clean up the oil spill.
- Workers' unions in France are protesting the change in their retirement age from 60 to 62.
Video explaining the differences