Dennis’ or Dennis’s?

The word Dennis’ is a correct singular possessive form of the name Dennis. E.g., “Dennis’ house is near mine.” However, Dennis’s is the more popular singular possessive of the name Dennis. E.g., “Dennis’s girlfriend works with me in the bank.”

Here is a helpful chart that shows the singular forms of the name Dennis.

Singular possessiveDennis’s / Dennis’

The rules and trends concerning the extra “s” after the apostrophe for possessives vary depending on who you ask. Therefore, both Dennis’ and Dennis’s are common and acceptable singular possessive forms for the name Dennis.

Here are some examples of the different forms in context.

  • Singular: Dennis is coming over for lunch later.
  • Singular possessive: Dennis’s Restaurant serves great food.
  • Singular possessive: Dennis’ dog is a cocker spaniel.

In regular everyday writing, the choice of which form to use is yours. However, some people prefer to use the version without the “s” after the apostrophe when the following word is awkward.

For example, another word beginning with “s” or “d” after Dennis can be a little difficult to pronounce. However, make sure you are consistent throughout your text by using the same version.

Perhaps you still have doubts about how to use the possessive form of Dennis. If so, please keep reading the rest of the article so you can see how to use the possessive correctly in AP Style and the Chicago Manual of Style.


The term Dennis’ is a correct singular possessive form of the name Dennis.

However, according to Google Ngram, it is not as popular as Dennis’s.

Furthermore, in AP Style, you should use the version Dennis’ because it is a proper noun that finishes in “s.”

  • Dennis’ degree is in physics.

Also, sometimes people use the possessive version without the apostrophe when the following word sounds awkward with an extra “s.” This could e.g., be the case if the following word starts with a “d” or an “s.”

  • Dennis’ sister lives in my apartment block.
  • Dennis’ dog is very aggressive.

However, if you choose to use Dennis’ on these occasions, you must use this version throughout the document.


The possessive form Dennis’s is also a correct singular possessive form of the name Dennis. Therefore, you use it to indicate that something belongs to a person named Dennis.

Dennis’s is the most common version of the possessive in American and British English, although the alternative is not far behind in terms of frequency.

Furthermore, the Chicago Manual of Style states that you should use Dennis’s.

  • Dennis’s garden has a swimming pool and hot tub.

In other types of writing, people often omit the “s” when the following word begins with “s” or “d.” Just be aware that if you do this once in a document, you must do it for the same type of words throughout the text.