A semiconductor memory device includes a stack structure including electrodes and insulating layers alternately stacked on a substrate, and a vertical channel structure penetrating the stack structure. The vertical channel structure includes a semiconductor pattern and a vertical insulating layer between the semiconductor pattern and the electrodes. The vertical insulating layer includes a charge storage layer, a filling insulating layer, and a tunnel insulating layer. The vertical insulating layer has a cell region between the semiconductor pattern and each electrode and a cell separation region between the semiconductor pattern and each insulating layer. A portion of the charge storage layer of the cell region is in physical contact with the tunnel insulating layer. The filling insulating layer is between the semiconductor pattern and a remaining portion of the charge storage layer of the cell region.