An ultrasonic transducer, and an ultrasonic wave generating apparatus and an ultrasonic system including the same. The ultrasonic transducer includes a light-absorbing layer configured to absorb light incident on the light-absorbing layer and to generate heat based on the absorbed light; and a thermoelastic layer which is disposed on the light-absorbing layer and which is configured to thermally expand based on the heat to generate ultrasonic waves.