Scientific modeling (SM) is a core practice of science and an important component of scientific literacy. Supporting students in developing the competence to construct, use, evaluate, and revise models is hence of particular relevance. While research has shown that spatial visualization (SV), a core component of spatial ability, is correlated with students' SM performance, it is unclear which role SV plays in students performing the four elements of SM: the construction, the use, the evaluation, and the revision of models. This study analyzes the role of SV in the performance of a series of SM tasks by 279 students in Grades 4 and 7. The findings indicate that SV affects students' performance in SM but that the effect is more significant in Grade 4 than in Grade 7. More specifically, SV is significantly predictive for model revision in Grade 4, but significant for model evaluation in Grade 7. However, there was no gender difference in the effect of SV on SM. The implications are that science teaching and learning must better attend to supporting younger students through visual aids when engaging them in SM. The study also suggests that further studies are needed to understand the different cognitive processes involved in students' SM and their complex interplay.