Scary moment for Sarah Hyland -- cops say her home recently got hit by intruders after she says she saw a couple men in masks leaving on her security cameras.

Law enforcement sources tell TMZ ... the "Modern Family" star's Los Angeles area home was burglarized last Saturday night -- right around sunset, mind you, while it was still daylight out -- and the suspects ended up smashing a glass window to gain entry into her crib.

Luckily, our sources tell us Sarah was out of town at the time of the incident -- but she was still involved. We're told she actually ended up seeing the dudes who broke in with her own eyes.

It wasn't in person, however ... our sources say Sarah ended up telling police she got an alert from her home security system -- and when she pulled up the live feed on her phone she witnessed two masked men walking right out the front door!!!

We're told cops were called to Sarah's home and they swept the house to make sure nobody was still lurking behind ... but our sources say the place was a ghost town by then, and the crooks were long gone.

Unclear what, if anything, was stolen and how much those items might be worth at this point -- we're told Sarah needs to do an inventory check when she gets back to figure out what may be missing here, and the cops will take it from there.

The case is currently under investigation ... and cops have yet to make any arrests.

Sarah's among a growing list of celebs who have been victims of home burglaries this year ... including Marlon Wayans and Bhad Bhabie, among others.