Nikephoros Xiphias (Greek: Νικηφόρος Ξιφίας) was a Byzantine military commander during the reign of Emperor Basil II. He was the governor of Plovdiv in Thrace. In 1001 he led a successful Byzantine campaign in north-eastern Bulgaria and captured the old Bulgarian capitals Pliska and Preslav.
In 1014 he was among the Byzantine commanders during the battle of Kleidion. The Bulgarians under Emperor Samuil had built a thick wooden wall to prevent further enemy invasions. When the Byzantines were desperate after the heavy casualties they suffered in the futile attempts to assault the wall, Xiphias and his troops managed to find a path which led them into the Bulgarians' rear. As a result the Byzantines achieved a major victory, which brought the end of the First Bulgarian Empire four years later. In 1022, he allied himself with Nikephoros Phokas Barytrachelos and revolted against Basil II. The rebellion quickly proved abortive as Xiphias had Phokas assassinated, whereupon the latter's supporters abandoned the rebellion. Xiphias was then forced to surrender to the emperor. He was tonsured and banished, while his estate was confiscated.