Have you recently developed a crush? Connected with an old classmate? Accepted your boss' friend request? For better or worse, it could be useful to see who is visiting your profile. Does Facebook offer a way to see who's viewed your profile or posts?
Despite the rumors you may have heard over the years, the answer is a resounding no. The concept of Facebook profile views is a pure myth. The Facebook Help Center states:
No. Facebook doesn't let you track who views your profile or your posts (ex: your photos.) Third-party apps are also unable to do this.
If you come across an app that says it can show you who's viewing your profile or posts, please report the app.
Note Facebook's emphasis on third-party apps: Chances are you've encountered a website or mobile app boldly claiming its service allows you to "See who views your profile!" Not only are those third-party clients lying, but they could be collecting your personal information or infecting your device with malware. Whatever their intention, all of these apps are scams.
For more info, check out Facebook's data policy.