An apostrophe is most commonly used to indicate possession and omission of letters in words.

Using apostrophes to indicate the possessive form:

  • add 's to singular and plural nouns not ending in -s and to indefinite pronouns
    • Katherine's horse
    • someone's notebook
    • The horse was Katherine's
    • Men's room
    • children's game
  • add ' only to singular nouns ending in s IF it does not make pronunciation difficult
    • boss's desk
    • Moses' wife
    • James' snake
  • add ' only to plural nouns ending in -s
    • boys' wagon
    • students' dormitory 

Using apostrophes to indicate omission of letters in words:

  • use an apostrophe to replace omitted letters, such as in contractions
    • can't (cannot)
    • isn't (is not)
    • it's (it is)
    • let's (let us)
    • we're (we are)
    • won't (will not)

Note: Do NOT use an apostrophe with possessive pronouns (his, hers, its, ours, yours, theirs, whose):

  • The horse was hers.
  • The horse ate its food.

Gain extra practice using the StudyMate activities below.

Set 1 


Last Updated: 8/29/13