The relative speed concept was chosen since it is linked with the relative nature of motion and it is likely that the students would harbor many alternative conceptions about it. The research objective was to identify the various ways students conceive relative motion. Qualitative data collected in various forms of representation received a categorization analysis. Several models of students' understanding about relative motion had been identified. Suggestions are offered to the classroom teacher to help his students understand relative motion. [For the full proceedings, see ED619611.]