A single-ended sense amplifier and a memory device including the same are presented. A sense amplifier, which senses and amplifies data of a memory cell, may include a precharge circuit pre-charging a data line which is connected to the memory cell and provides a sensing voltage, and a reference line which provides a reference voltage, with a power supply voltage; a reference voltage generating circuit which generates the reference voltage by discharging the reference line based on a reference current, and adjusts an amount of the reference current based on the data of the memory cell; and a comparator which compares the sensing voltage and the reference voltage, and outputs a comparison result as the data of the memory cell.