In much previous research, listeners' rating data have served as a dependent variable todemonstrate the effects of age of learning, length of residence, and motivation on L2 users'degree of foreign accent. However, the role of speaking rate in such judgments has not beenascertained. To gain new insight into this relationship, we carried out two experiments involvingsentence-length utterances produced by English L2 users. In the first, we observed a significantcurvilinear relationship between speaking rates and accentedness and comprehensibility judgmentsof utterances produced by users from a variety of L1 backgrounds. In the second experiment, bymanipulating rates with speech compression-expansion software, we established that this effectwas due to the rate differences themselves, rather than to differences in L2 proficiency that mightco-vary with rate. In both experiments the listeners tended to assign the highest ratings to L2speech that was somewhat faster than the rates generally used by L2 users; however, both veryfast and very slow speech tended to be less highly rated. Researchers who use listener rating datashould be mindful of the potential confounding effect of speaking rate in their data.