Parent PLUS Loan Improvement Act of 2018 This bill amends the Higher Education Act of 1965 to modify the applicable terms and conditions with respect to Federal Direct PLUS Loans to parent borrowers (i.e., parent PLUS loans). Specifically, it reduces the interest rate and eliminates the origination fee for a parent PLUS loan disbursed on or after July 1, 2018. The Department of Education must ensure, prior to disbursement, that a parent PLUS loan borrower receives counseling that includes comprehensive information on the terms, conditions, and responsibilities with respect to the loan. The bill makes a parent PLUS loan eligible for the income-contingent and income-based repayment plans. Additionally, it makes a consolidation loan that repays parent PLUS loan eligible for the income-based repayment plan.