In the comments of our Word Fact post about the difference between affect and effect, Carolyn K. wrote:
Please, please, please, I beg you to do Lets vs. Let’s. Every sports team’s media/PR department does it wrong, and it drives me absolutely out of my mind!
This lets us address another great topic, since these terms are often confused—let’s figure it out!
Lets without an apostrophe is the third-person singular form of the verb let, meaning “to allow or permit”: She lets the dog out every morning.
Let’s with an apostrophe is a contraction of “let us,” which is used in all varieties of speech and writing to introduce a suggestion or request: Let us consider all the facts. Because “let us” often sounds overly formal, the contracted form, let’s occurs more frequently in colloquial speech and writing: Let’s go, Tigers! Let’s forget this ever happened.
Sometimes you’ll see redundancy with the use of let’s: Let’s you and me get out of here. This, of course, literally means, “Let us you and me get out of here.” If “you and me” is treated as an aside here, it can function to elaborate on the subject for emphasis and clarification. However, if not treated as an aside, the above example would be considered nonstandard English.
Whether it’s intentional or not, the fact remains the same: let’s and lets are commonly misunderstood. Let’s be kind to those that make encouraging signs, and we’ll double check our apostrophe use the next time we’re cheering for our favorite team. Let’s go, grammar lovers!