Spatial ability is a core component of intelligence and a key predictor of academic achievement in science, technology, engineering, and mathematics (STEM) domains (Wai et al., 2009). However, substantial individual differences in spatial cognition have been observed (Casey, 2013). Many children fail to develop spatial abilities to a level that enables them to succeed in STEM fields, prompting calls for efforts to enhance children’s spatial abilities (Newcombe, 2017). Despite this, the factors underlying individual differences in spatial abilities and their relationship to STEM learning remain unclear, posing challenges for the development of targeted interventions. There is an abundance of research demonstrating a relationship between spatial ability and mathematics. However, the underlying mechanisms contributing to this relationship remain unclear. One factor that may play a role is working memory. This study aims to investigate the unique and shared contributions of working memory and spatial ability to math performance, providing new insights into the mechanisms that link these constructs. Approximately 250 upper elementary school children were recruited in the Netherlands. They completed measures of working memory, spatial abilities, nonverbal intelligence (included as a control variable), and math performance. The correlations among these variables will be analyzed.