So I was taught that I should use apostrophes when something possesses something else, but I'm not sure about the use of it's in the following situation:

...and they found their way to a castle. It's walls were made of pure gold.

My question is, should I use It's because the apostrophe means that the castle has possession of the wall, or should I not because it's is generally understood to be a concatenation of "it is"? Or perhaps I should use Its' walls?

  • As the roundabout answers imply, the example you cited is simply incorrect; it should have said "Its walls. . ." You have it right, but many AmE writers get this wrong. I see it nearly every day. Mar 27, 2015 at 7:57

2 Answers 2


"It's" is a contraction of "it is" ("it's about time") or "it has" ("it's been two years"). "Its" Is the possessive (belonging to it).

Beware of simple rules. In English, if it's simple, it's probably incomplete.

  • An easy way to remember this is that "it" can only be singular, so "its" isn't ambiguous. Pretty much every other noun (except pronouns) can be plural or possessive, so the 's form is necessary. Mar 27, 2015 at 3:14
  • You shouldn't answer questions which are clearly duplicates. Mar 28, 2015 at 2:08

I wouldn't ponder too much about the fine point on the possessive pronoun used for the castle's wall.

This is what I mean:

I decided not to buy that house after I discovered its roof leaked like a sieve.

I just stated the house's roof leaked; you have another way of stating something being part of something else, that is by way of using the preposition of:

I decided not to buy that house after I discovered the roof of the house leaked like a sieve.

Also, keshlam has a very important point: [it's] does not denote possession, in this case possessive pronoun that should be used there is "its"

Remember this example always:

It's a wise dog that scratches its own fleas!

I learned that from Strunk & White many many years ago.

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