Because of an increasing quality concern for higher education, additional attention is being paid to new educational principles with a more student- and competence-centred vision. Project-based education is one of the learning environments congruent with these principles. Ideally, the students in this learning environment are assessed by suitable assessment modes, like peer assessment and co-assessment. This article evaluates this obviousness critically, focusing on how instructors and students perceive these project-based learning environments and group-based assessment methods. The main conclusion is that it seems very difficult to create a complete assessment procedure in which both parties' assessment expectations are being met. This is due to crucial contradictions in opinions about assessment in project-based education.