About half of kinship families live in poverty, and one third of them receive financial assistance such as Temporary Assistance for Needy Families (TANF) and foster care payments. This study selected children who remained in kinship care (N = 267) for three waves from nationally representative data and examined the longitudinal associations among poverty, economic pressure, financial assistance, and children’s behavioral health outcomes in kinship care. Results from multilevel mixed-effects generalized linear models indicated that having economic pressure and receiving TANF were associated with increases in kinship children’s internalizing and externalizing problems. Receiving TANF exacerbated the effects of poverty on children’s externalizing problems, while receiving TANF buffered the negative effects of economic pressure on children’s internalizing problems. However, internalizing and externalizing problems were in the normal range, on average. The results imply that child welfare workers should assess kinship families’ subjective economic pressure in addition to objective poverty. Furthermore, policy makers should reconsider who receives TANF, how TANF is distributed to kinship families, and whether TANF meets kinship families’ needs.