This study addresses gender assignment in six North Scandinavian varieties with a three-gender system: Old Norse, Norwegian (Nynorsk), Old Swedish, Nysvenska, Jamtlandic, and Elfdalian. Focusing on gender variation and change, we investigate the role of various factors in gender change. Using the contemporary Swedish varieties Jamtlandic and Elfdalian as a basis, we compare gender assignment in other North Scandinavian languages, tracing the evolution back to Old Norse. The data consist of 1,300 concepts from all six languages coded for cognacy, gender, and morphological and semantic variation. Our statistical analysis shows that the most important factors in gender change are the Old Norse weak/strong inflection, Old Norse gender, animate/inanimate distinction, word frequency, and loan status. From Old Norse to modern languages, phonological assignment principles tend to weaken, due to the general loss of word-final endings. Feminine words are more susceptible to changing gender, and the tendency to lose the feminine is noticeable even in the varieties in our study upholding the three-gender system. Further, frequency is significantly correlated with unstable gender. In semantics, only the animate/inanimate distinction significantly predicts gender assignment and stability. In general, our study confirms the decay of the feminine gender in the Scandinavian branch of Germanic.