Children's socioeconomic status (SES) is linked to disparate access to resources and affects social behaviors such as inclusion and resource allocations. Yet it is unclear whether children's essentialized view of SES (i.e., believing SES is immutable) or subjective social status (SSS) influences behavioral biases toward high- versus low-SES peers. We measured 4- to 9-year-old children's SES essentialism and SSS to test whether these predict inclusion and resource allocations to high- versus low-SES peers (N = 127; from a midsize city in the Southeastern United States; 49.6% female; parent-reported 54.2% White, 2.8% Black, 8.3% Latine, 5.6% Asian, 1.4% another race, 27.8% multiracial, 43.3% not provided). We also compared children's SES beliefs to their parent's. Children's SES essentialism and SSS decreased across the ages tested, and children reported higher SSS than their parents. Parents' SES essentialism predicted younger (but not older) children's SES essentialism. Moreover, SES essentialism mediated the negative relationship between age and preference for including high-SES peers, while SSS mediated the negative relationship between age and preference for allocating more resources to high-SES peers. This suggests that beliefs about the nature of SES may influence sociorelational behavior like including or excluding others, while perceived social status (SSS) may influence resource allocations. Furthermore, older children and those with lower SES essentialism included low- versus high-SES peers more often while older and lower SSS children distributed more resources toward low- versus high-SES peers. Thus, children's SES essentialism and SSS may also influence their behaviors to either perpetuate or rectify inequality.