Working Families Relief Act This bill amends the Internal Revenue Code to increase and expand tax incentives for employer-provided dependent care assistance. The bill increases the limit on the amount excludible from the gross income of an employee for employer-provided dependent care assistance and requires annual inflation adjustments to such increased limit after 2018. The bill also allows tax credits for: (1) small employer dependent care assistance program start-up costs, and (2) employer matching contributions for dependent care assistance programs.