Tax Parity for Health Plan Beneficiaries Act of 2013 - Amends the Internal Revenue Code to: (1) exclude from an employee's gross income employer-provided accident and health plan benefits extended to a domestic partner or non-dependent, non-spouse beneficiary eligible to receive such benefits under an employer plan (i.e., "eligible beneficiary"); (2) exempt such benefits paid to eligible beneficiaries from otherwise applicable employment and unemployment taxes; (3) allow self-employed individuals a tax deduction for the health insurance costs of their eligible beneficiaries; (4) allow tax-exempt voluntary employees' beneficiary associations to provide sick and accident benefits to the domestic partners and non-dependent, non-spouse beneficiaries of their members; (5) allow reimbursement of the medical expenses of an eligible beneficiary from a health savings account (HSA); and (6) extend tax-exempt medical benefits to the eligible beneficiaries of retired employees

Directs the Secretary of the Treasury to provide guidance relating to reimbursements from a flexible spending arrangement and a health reimbursement arrangement attributable to an eligible beneficiary as defined by this Act.