Correct spelling


Correct spelling, explanation: English possessive is expressed with ’s at the end of the word. For example, a sandwich that belongs to John is John’s sandwich. If the noun is regularly plural (ends with s) we do not add the possessive s at the end but the noun is left just with an apostrophe. This is why boys’ is the correct form of writing, not boys’s.

Definition of boys:
noun, possessive, something that belongs to more than one boy
The boys’ football team in our school is the best in the town!
For the striped shirts look in the boys’ section of the shop.

Incorrect spelling


Incorrect spelling, explanation: this form of possessive is wrong since in regular plural nouns (these ending with s) the apostrophe is not followed by s. Therefore the correct form is boys’, without another s. The form boys’s doesn’t exist.