Children’s early numerical competencies are of great importance for later academic achievement. Young children gain these competencies in the context of the home numeracy environment (HNE). Additionally, child characteristics and families’ socioeconomic status (SES) are associated with children’s competencies. In this study, we investigated parents’ occupations (i.e., STEM or non-STEM occupation) as a specific aspect of the SES to understand whether parental occupations are associated with children’s numerical competencies and whether such an association may depend on the HNE. We analysed data from a sample of N = 190 children (Mage = 63.58 months; SD = 4.41) at two measurement points. Correlational analyses and crossed-lagged models were conducted to predict children’s numerical competencies by a global measure of the HNE and parental STEM vs. non-STEM occupations. We found significant associations between parents’ learned and current occupations and the HNE. Further, significant associations between parents’ learned occupations and children’s numerical competencies were observed. However, parents’ current occupations were not significantly associated with children’s numerical competencies. Consequently, more specific facets of the SES instead of a global measure seem to be associated with children’s numerical competencies. A greater focus on specific differences between family characteristics and their potential impact on children’s HNE and the development of their numerical competencies seems expedient.