Children from lower socioeconomic status (SES) families are at increased risk for anxiety problems, though knowledge of the pathways by which SES predicts children's anxiety outcomes remains scant. Limited work suggests SES as a moderator of links between early development and anxiety outcomes but has not used a longitudinal framework or a multimethod approach. In this preregistered study, SES was tested as a simultaneous moderator of putatively biologically (error-related negativity [ERN]) and contextually (authoritarian parenting) based pathways of anxiety risk from ages 3 (M[subscript age] = 3.59), 4 (M[subscript age] = 4.57), and 5 (M[subscript age] = 5.52) [N = 121; 59% female]. Families were largely White and Non-Hispanic and reported a broad range of income (less than $15,000 to $90,001 or greater) from 2014 to 2017. We hypothesized that putatively biological pathways would be the strongest predictors of child outcomes at high SES and that putatively contextual pathways would be the strongest predictors of child outcomes at low SES. Consistent with expectations, smaller ERN across ages 3 and 4 was associated with greater anxious behaviors at age 5, but only at high SES. SES did not moderate parenting-based pathways of risk. Results are partially consistent with previous work suggesting that putatively biological pathways are more robust predictors of child outcomes at high SES than at low SES.