Ninety-six percent of the cabin crew voted in favour of the strike, the UFO union announced.
The vote does not officially end until noon on Monday, but union officials said they were already certain that they had the necessary majority to begin a strike.
UFO is fighting to get a 15 percent wage increase over a 12-month period for its members. Lufthansa, which employs some 16,000 cabin crew members, has offered a deal that includes a 10 percent salary increase that would occur over the next 14 months.
Talks between the union and Lufthansa broke up in January without agreement, and UFO has since staged two temporary strikes, forcing the airline to cancel several flights.
More negotiations over the weekend will determine whether workers will actually strike.