Is 'Sir' Capitalized?

By Carly Forsaith, updated on March 22, 2023

Are you wondering, "Is 'sir' capitalized?" And if so, when? Look no further; in this article, you’ll learn when to capitalize honorifics and when not to.

In short:

  • You should capitalize ‘sir’ when beginning a salutation in a letter when it’s the first word of the sentence and when it’s an honorific followed by the person’s name.

Is 'Sir' Capitalized?

First of all, what does ‘sir’ mean? It’s a noun, and it’s defined by the Cambridge Dictionary as “used as a formal and polite way of speaking to a man.”

It’s an honorific, just like ‘dame’ or ‘Lord.’

Honorifics are not to be confused, however, with titles like ‘madam,’ ‘miss,’ etc.

So when should you capitalize ‘sir’? Let’s find out!

When 'Sir' Is Capitalized

There are four instances in which you should capitalize ‘sir’ and that’s:

  • When it’s the first word of the sentence
    Sir, is this your hat?
  • When all the other words are capitalized, too
  • When the word begins a salutation in a letter
    Dear Sir,
  • When it’s used as a title and is followed by the name of the person
    I sat right behind Sir Elton John.

When 'Sir' Is Lowercase

This is pretty straightforward: basically unless it’s one of the four contexts described above, you should use a lowercase ‘s’ in the word ‘sir.’

Using ‘sir’ as a way to be polite when addressing a man you don’t know? Use ‘sir.’ Talking about someone who’s been knighted, but you aren’t using their name? Use ‘sir.’

Examples of ‘Sir’ in a Sentence

Let’s take a look at some example sentences that use ‘sir’ so you can see in context when they’re capitalized and when they aren’t.

I think Sir Ian McKellen is my favorite sir.

Please sir, can I have some more?

Dear Sir, I am writing you this letter to share some news with you.

Sir, your patients are waiting.

Now he’s been knighted you’re obligated to call him ‘sir.’

Everyone was hoping Sir Lewis Hamilton would be present.

Sir, welcome to the Babylon Hotel.

Welcome to the Babylon Hotel, sir.


Do you mind if I call you ‘sir?’

Concluding Thoughts

So there you have it; there are only four circumstances in which you should capitalize ‘sir,’ and outside of those, you should always use a lowercase ‘sir.’

Let’s review. Capitalize ‘sir’ when:

  • It’s the first word of the sentence
  • All the other words are capitalized, too
  • The word begins a salutation in a letter
  • It’s used as a title and is followed by the name of the person

If you found this article helpful and would like to learn about more grammar rules, why not head to our blog?

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Written By:
Carly Forsaith
Carly Forsaith is one of the lead freelance writers for Carly is a copywriter who has been writing about the English language for over 3 years. Before that, she was a teacher in Thailand, helping people learn English as a second language. She is a total grammar nerd and spends her time spotting language errors on signs and on the internet.

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