This article analyses the use of peer and self-assessment in oral presentations as complementary tools to assessment by the professor. The analysis is based on a study conducted at the University of Girona (Spain) in seven different degree subjects and fields of knowledge. We designed and implemented two instruments to measure students' peer and self-assessment, and a rubric to guide the assessment process. Results were compared with the marks awarded by the professor. In contrast with studies by other authors, which show a high correlation between these different assessment systems, our study revealed significant deviations. Applying peer and self-assessment to oral presentation activities also demonstrates their formative value above and beyond their summative usefulness.