She finished at 11-under 205 for the 54-hole tournament at Bogstad, a parkland course that is Norway's oldest. It was her 67th career title and record-35th on the Ladies European Tour.
Davies, who won the 2002 Norwegian Masters on the same course, eagled the second and 15th holes. She also had five birdies.
Ellen Smets, a rookie from Belgium, was second at 211 after closing with a 70. Nikki Garrett (70) and Virginie Lagoutte (71) tied for third at 212.