Mathematical modelling is a complex process consisting of several steps, which can also be carried out with the use of digital tools. This paper takes a closer look on how students perceive the DGS GeoGebra when learning mathematical modelling, how their confidence in their tool competencies changes when using the software to do modelling, and if the learning outcome concerning modelling competencies is influenced by programme-related self-efficacy or attitudes towards learning with the digital tool. Results from both qualitative and quantitative evaluations of a study with approx. 300 grade 9 students are reported.