HMN? How do I lock doors in minecraft? VILLAGERS INVADING? HMN? HMN? HMN?

If you swap the wooden doors to iron doors and place a button or lever on either side next to it, villagers won't be able to open the door, but you still will be able to.

I hope this works out for you. Happy Minecafting!

Well, don't put your house next to a village for starters, and what Lachie said is true, using iron doors will prevent the villagers from seeing your house (or whatever else it might be) as valid housing so they will not go into it because it is not part of their "village". Anything with a roof and a wooden door will be represented as valid housing for villagers, so just keep that in mind.