Miranda Cosgrove Sues -- Tour Bus Crash Left Me 'Disfigured'

"iCarly" actress Miranda Cosgrove claims she was "disfigured and disabled" in a nasty 2011 tour bus crash ... this according to a new lawsuit obtained by TMZ.

We broke the story ... Cosgrove -- who also happens to be a pop star -- was traveling on a bus in Illinois with 5 other passengers when it slammed into an overturned tractor-trailer that was laying across the highway.

Cosgrove suffered a broken ankle in the wreck ... and was forced to cancel the rest of her tour.

Now, TMZ has learned ... the 20-year-old and her mother (who was also on board) are suing the driver of the bus, the driver of the tractor and the transportation companies ... claiming the whole thing could have been prevented.

In the suit, the Cosgroves claim both drivers were operating their vehicles in an unsafe manner and failed to keep a "safe and proper lookout."

They also claim the tour bus driver failed to hit the brakes in time (...duh).

According to the lawsuit, filed in federal court in Illinois, the women claim they were each "disfigured and disabled" and "have lost their normal lives" as a result of the crash ... though they don't give specific details about their injuries.

They're suing for unspecified damages ... demanding more than $50k each.

Calls to the transportation companies have not been returned.

Fun Fact -- Miranda played the snobby little rich girl in "School of Rock." Great flick ...