It is generally difficult for teachers to assess students’ abilities in tackling mathematical modelling problems. Apart from the fact that there can be multiple solutions to and multiple ways of solving modelling problems, it is also not a trivial task to assess mathematical modelling competencies. It is widely agreed that the process of mathematical modelling is probably more valuable than the product itself, and assessing students’ competence or ability to carry out a process often require observation over a period of time. In this chapter, the reasons for assessing mathematical modelling will be presented first, followed by a discussion on what can or should be assessed. The chapter ends with suggestions on how one might assess mathematical modelling carried out either in the classroom or as a project.