A semiconductor memory device includes insulating patterns and gate patterns alternately stacked on a substrate, a channel structure that intersects the insulating patterns and the gate patterns and connected to the substrate, a charge storage structure between the channel structure and the gate patterns, and a contact structure on the substrate at a side of the insulating patterns and the gate patterns. One of the gate patterns includes a first barrier pattern between a first insulating pattern of the insulating patterns and a second insulating pattern of the insulating patterns adjacent the first insulating pattern in a first direction perpendicular to a main surface of the substrate, the first barrier pattern defining a concave region between a first portion of the first barrier pattern extending along the first insulating pattern and a second portion extending along the second insulating pattern, and a metal pattern in the concave region.