Although at first MOOC (Massive Open Online Courses) did not use peer reviews, this kind of assessment has increasingly demonstrated the benefits that it can contribute to this type of course by improving the learning process, increasing decisions making abilities, and developing several other academic skills. Other MOOC assessment instruments do not provide students with these opportunities. This paper discusses the results obtained by the most commonly used massive online course platforms, detailing their features and limitations, as well as the experience in the implementation and use of a peer review system for a course of more than 7300 students. This study also comments on how evaluation rubrics are created, along with the final results, and the impact of the inclusion of this type of evaluation in MOOC.