This study examined the causal relationships between parenting stress and self-efficacy of Korean mothers with an infant according to employment status using the second through fourth wave data of the Panel Study of Korean Children (PSKC). Autoregressive cross-lagged modeling was performed to test the longitudinal reciprocal relationships between the two constructs. Our results indicated that both maternal parenting stress and self-efficacy were consistent over time. The results also indicated that there was a significant cross-lagged effect of maternal parenting stress on their self-efficacy, rather than vice versa. No differences between working and non-working mothers were found in the relationship between the two constructs.