Lewis’ or Lewis’s?

The term Lewis’s is the more common way to form the singular possessive of Lewis. For example, “Lewis’s book collection is extensive.” However, the word Lewis’ without an additional “s” at the end is also correct, and it is a matter of preference which you use. For instance, “Lewis’ car is parked outside.”

The following table shows the singular forms of the name Lewis.

Form	Example
Singular	Lewis
Singular possessive	Lewis’ / Lewis’s

As you can see, you can form the singular possessive in two ways because the word Lewis ends with an “s.”

According to Google Ngram, the more common possessive form is Lewis’s. This is also the form you should follow for APA Style and Chicago Manual of Style.

Alternatively, you can use the less popular version, which is Lewis’. You should use this version with no additional “s” if you follow AP Style.

Considering the above rules, both of the following sentences are correct:

• Lewis’s research findings were groundbreaking.
• Lewis’ dog is well-trained.

However, if you start using one version in a text, you should continue with that version until the end.

Perhaps you still have doubts about the different forms of the name Lewis. If so, please continue reading the rest of the page to avoid making mistakes in the future.

Lewis’s

The term Lewis’s is the more popular singular possessive version of the name Lewis. Therefore, you use it to indicate that something belongs to a person named Lewis.

Furthermore, style guides like the Chicago Manual of Style and APA Style suggest that you should use this singular possessive form with the additional “s.”

• Lewis’s dedication to his work is evident in his achievements.

Sometimes people avoid adding the “s” at the end when the word after it begins with “s.” However, this is just a preference, and the other version is still acceptable.

• Correct: Lewis’ success was celebrated by his peers.
• Correct: Lewis’s success was celebrated by his peers.

Although, whichever version you choose to use, you must be consistent and use the same version throughout the text.

Lewis’

The term Lewis’ with an apostrophe and no additional “s” is a singular possessive form of the name Lewis.   

However, it has never been as popular as Lewis’s with an “s,” although Lewis’ is the correct version if you use AP Style.

• Lewis’ house is located in a quiet neighborhood.

However, although Lewis’s is more common, Lewis’ is clearer because if the following word starts with an “s,” then you avoid having three instances of the letter “s” in a row.

• Lewis’ studies often take him abroad.

Also, if you choose to use the version without the second “s,” you should use that version throughout the document, regardless of whether the following word starts with “s.”