Strengthening Protections for Social Security Beneficiaries Act of 2018 TITLE I--STRENGTHENING OVERSIGHT AND BENEFICIARY PROTECTION (Sec. 101) This bill requires the Social Security Administration (SSA) to make annual grants to each state's protection and advocacy system for the purpose of conducting reviews of representative payees under the Supplemental Security Income (SSI) program and the Old Age, Survivors, and Disability Insurance (OASDI) program. The SSA must also conduct periodic onsite reviews of individual and organizational payees. (Sec. 102) The bill lessens certain monitoring requirements with respect to specified family members who are serving as representative payees. (Sec. 103) The SSA must: (1) enter into agreements with each state for the purpose of sharing information to identify represented minor beneficiaries who are in foster care; and (2) determine the appropriate representative payee for any represented minor beneficiary who has entered foster care, exited foster care, or changed foster care placement in a given month. The Government Accountability Office must report to specified congressional committees on certain issues related to represented minor beneficiaries in foster care. (Sec. 104) The bill modifies provisions related to overpayment liability with respect to a represented minor beneficiary in foster care. (Sec. 105) The SSA must report to specified congressional committees on certain issues related to representative payment with respect to SSI and OASDI benefits. TITLE II--IMPROVING PAYEE SELECTION AND QUALITY (Sec. 201) The bill provides for advance designation of representative payees. (Sec. 202) In general, an individual who has been convicted of a felony, or of an attempt or a conspiracy to commit a felony, may not serve as a representative payee. (Sec. 203) An individual who has a representative payee may not also serve as a representative payee.