Ensuring Child Care for Working Families Act of 2012 - Amends part A (Temporary Assistance for Needy Families) (TANF) of title IV of the Social Security Act to revise funding requirements for child care assistance to: (1) guarantee child care assistance for a family with a dependent child requiring such care, if the total income of the family does not exceed 200% of the poverty line and the child care assistance will enable an individual in the family to accept employment, remain employed, or participate in an education or training activity; and (2) include Indian tribes and tribal organizations as entities eligible for state grants in amounts equal to those granted to states.