They claim the facility's negligence resulted in the death of a loved one.
A video shows 78-year-old Barbara Jones Davis wandering outside of Wesley Enhanced Living at Stapeley last July in Germantown.
Davis was visually impaired and suffered from dementia.
The lawsuit claims she was left unattended for 23 minutes before she fell.
"No family should have to suffer the pain our family has suffered as a result of the loss of our loving mother," said daughter Pamela Davis Edwards.
The lawsuit alleges the 78-year-old opened an unguarded and unlocked door on the side of the facility before wandering outside alone.