Bryant, Gianna and seven others died when the helicopter they were in crashed in fog on 26 January.
In the lawsuit, Vanessa Bryant says the pilot was negligent for flying in such poor weather.
It was filed shortly before a memorial service held in Los Angeles.
Island Express Helicopters and the pilot, Ara George Zobayan, had a "duty to use that degree of care that an ordinarily careful and prudent pilot would use under the same or similar circumstances," the suit says.
It alleges that Zobayan - who died in the crash - did not assess weather data before taking off.
The suit says the pilot did not abort the flight despite the treacherous conditions.
The company authorised the flight "with full knowledge that the subject helicopter was flying into unsafe weather conditions", the complaint says.
Ms Bryant is seeking undisclosed compensatory and punitive damages.
Island Express Helicopters has suspended operations.