Yes, they are basically the same. Oscilltory motion refers to any motion which repeats itself over a period of time. Harmonic motion is a motion in which a restoring force acts to cause oscillation which has some relation to displacement caused. 

The eqauation for harmonic motion is- Force directly proportional to displacement to power n, when the n =1 or restoring force is proportional to displacement, it is called simple harmonic motion or SHM. So basically, every SHM is oscillatory but not the other way around.