This paper presents a cross-dialectal study of grammatical gender in Norwegian nominal phrases. Specifically, we investigate the decline of the feminine gender in three age groups across seven different dialects. The dialects vary in their morphological richness of gender marking: some dialects traditionally have more distinctive marking of the feminine gender. With an elicited production experiment, we investigate gender marking on the indefinite determiner and the definite suffix. We find that feminine gender is in decline in all dialects, but there are clear differences between the locations and between age groups. The feminine indefinite determiner ei is replaced by the masculine en at different rates and to a different degree in the various dialects. We furthermore find that the feminine definite suffix -a is retained in all locations except for Stavanger. We argue that the decline of the feminine gender can be explained by an interplay between the morphological richness of the given dialect and dialect contact. The former helps to retain the feminine as a separate category, while the latter accelerates the loss of the feminine.