Lindsay Lohan fears she is being targeted by a stalker.

People close to her and with knowledge of her recovery agree, and say the threat is so real that the Betty Ford clinic is taking measures to protect her.

Lohan has been receiving harassing phone calls and text messages from unknown numbers in recent days, with an unidentified person behind them.

Lindsay Lohan is being stalked, and not just by paparazzi.

The person behind the calls, whomever it might be, has been making disparaging statements about her recovery ... and her family. Guess that rules out MiLo.

Even scarier, the unknown person is saying he/she knows where Lindsay is staying and is watching her. Come on ... we all know she's staying at Betty Ford.

Still, officials are so concerned, they're moving their famous patient to a more secure, private facility and limiting her outings out of concern for her safety.

Keep safe, stay strong and get well, girl.