Anyone that can "see" your wifi network can "try" to connect to it. At the moment my computer is showing 8 nearby networks. If they, and your TV don't have the password they will not get in.
Anyway, to answer your question: Yes. From LG.com website:
Press the Home/Smart. ...
Click the Settings icon in the top-right.
Choose the All Settings. ...
Choose the Network menu from the left.
Choose Wi-Fi Connection if using Wi-Fi, or Wired Connection if using ethernet. ...
If on Wi-Fi Choose Advanced Wi-Fi Settings at the bottom. ...
Note the icons at the top with green circles.
Google is your friend