Dental caries remains a major public health problem among preschool children and is strongly influenced by behavioral risk factors, particularly frequent sugar consumption and inadequate toothbrushing. Outdoor activity and dietary vitamin D intake may contribute to oral health through their potential roles in vitamin D status and dental mineralization. This study examined whether outdoor activity and dietary vitamin D intake moderate the association between caries risk factors and dental caries status among preschool children. An analytical cross-sectional study was conducted among children aged 5–6 years in the Kedungdoro Community Health Center area, Surabaya. From a target population of 393 children, 200 participants were selected using simple random sampling. Data on sugary food and beverage consumption, toothbrushing habits, outdoor activity, and dietary vitamin D intake were collected using parent-administered questionnaires, while dental caries status was clinically assessed using the dmf-t index. Spearman’s rank correlation and hierarchical moderated regression analyses were performed. Among the 200 children, sugary food and beverage consumption (r = 0.737, p < 0.001) and poor toothbrushing habits (r = 0.744, p < 0.001) were strongly and positively associated with dental caries status. Outdoor activity was inversely associated with caries status (r = −0.355, p < 0.001), whereas dietary vitamin D intake was not significantly associated with caries status (r = −0.069, p = 0.333). In the final regression model, sugary food and beverage consumption (β = 0.401, p < 0.001) and poor toothbrushing habits (β = 0.350, p < 0.001) remained significant predictors, while outdoor activity showed an inverse association (β = −0.147, p = 0.009). Neither outdoor activity nor dietary vitamin D intake significantly moderated the associations between caries risk factors and dental caries. These findings highlight the importance of behavioral factors in preventing dental caries among preschool children.