One of my best friends.....

How often have you heard or used the following sentences?

One of my best friends are coming over for dinner tonight.

Or

One of my best friend is coming over for dinner tonight.

Which one of them is right? Actually, both of them are wrong! The sentences make sense, but they are grammatically wrong.

When you use the expression one of my…., you are talking about a singular subject, in other words only one subject. Therefore, the verb used is also singular.
Do not get mislead by the plural form of friend (friends) because what you are actually talking about is one of the many friends you have.

You are also talking about one of many friends and therefore, the noun is in the plural.

So remember:

The noun is in the plural form (friends)
The verb is in the singular form since you are talking about only one of the same kind. (is)

Look at other such sentences:

1. One of my books is missing.
2. One of these days, I will really get that car I have been talking about.
3. One of my mother’s best friends is taking us out for dinner tonight!
4. Isn’t this one of the stamps that you got me from the US?
5. One of the doctors has gone on leave.