Planetary science and planet exploration are disciplines that have always commanded a strong interest among the general public. In this context many opportunities exist for collaboration between amateur and professional astronomers. We shall discuss several aspects of the contribution of non-professional astronomers. This includes their valuable role in research, where amateur astronomers are active in several areas of planetology such as the active monitoring of the major planets and in minor body observations; and in popularization initiatives, where they play a valuable role as mediators between the professionals and a wider audience.