Provided is an apparatus and method for detecting a tap. The apparatus includes a sensor configured to detect a motion and output a signal corresponding to the motion, a gradient calculating unit connected to the sensor to calculate a gradient of the output signal from the sensor, a similarity determining unit connected to the gradient calculating unit to determine a similarity between a rising gradient and a falling gradient of a curve of the output signal, a tap determining unit connected to the similarity determining unit to determine detection of a tap according to the determination result of the similarity determining unit, and an output unit configured to output the determination result of the tap determining unit.