This study examined the bidirectional relationships among Chinese children's mathematics, executive functioning, and visual–spatial skills during their transition from kindergarten to primary school. Participants were 172 Cantonese-speaking Hong Kong children (mean age at Time 1 = 62.75 months; 88 male) and their parents. At Time 1 (kindergarten K3), children were administered the measures of mathematics (calculation and applied problems), executive functioning (working memory and inhibitory control), and visual–spatial skills. They were reassessed on these measures at Time 2 (primary 1) 1 year later. Results from the cross-lagged panel model showed that, controlling for child age, gender, and family socioeconomic status, children's visual–spatial skills at Time 1 were significantly predictive of their mathematics at Time 2 and children's executive functioning and visual–spatial skills reciprocally predicted each other across times. However, children's mathematics at Time 1 were not predictive of their executive functioning or visual–spatial skills at Time 2. The findings highlight the desirability of improving children's executive functioning and visual–spatial skills to promote their mathematical performance during the formal school transition. Copyright © 2020 Elsevier Inc. All rights reserved.