In this paper we investigate the value of collaboration scripts for promoting metacognitive knowledge in a project-based e-learning context. In an empirical study, 82 students worked individually and in groups on a project using the e-learning environment MyProject, in which the life cycle of a project is inherent. Students followed a particular collaboration script that combines individual and collaborative activities, aiming to promote individual and socially shared reflective thinking during the planning and evaluation phases of the project. We analysed group discussions and evaluation questionnaires, and the results provide evidence about the importance of the design variables considered in the collaboration script for cultivating metacognitive knowledge, such as project phase, roles undertaken by students, degree and type of interaction, type of activities and products, and activity sequencing. (Contains 3 tables and 4 figures.)