Lindsay Lohan is suing E-Trade ... because she thinks, the boyfriend-stealing "milkaholic" baby in their commercial was modeled after her ...

The baby was even named Lindsay.

Bottom line: she wants $100 million for her pain and suffering.

Lohan's lawyer said the actress has the same single-name recognition as Oprah or Madonna. She said, "Many celebrities are known by one name only, and E-Trade is using that knowledge to profit. They're using her name as a parody of her life. Why didn't they use the name Susan? This is a subliminal message. Everybody's talking about it and saying it's Lindsay Lohan."

The lawyer says Lohan is owed $50 million in exemplary damages, plus another $50 million in compensatory damages.