A semiconductor memory device includes a device isolation layer formed in a semiconductor substrate to define a plurality of active regions. Floating gates are disposed on the active regions. A control gate line overlaps top surfaces of the floating gates and crosses over the active regions. The control gate line has an extending portion disposed in a gap between adjacent floating gates and overlapping sidewalls of the adjacent floating gates. First spacers are disposed on the sidewalls of the adjacent floating gates. Each of the first spacers extends along a sidewall of the active region and along a sidewall of the device isolation layer. Second spacers are disposed between outer sidewalls of the first spacers and the extending portion and are disposed above the device isolation layer. An electronic device including a semiconductor memory device and a method of fabricating a semiconductor memory device are also disclosed.