Preserving Teacher Loan Forgiveness for Military Spouses Act of 2018 This bill amends the Higher Education Act of 1965 to modify the qualifying service requirement of the teacher loan forgiveness program for certain military spouses who are borrowers under the Federal Family Education Loan program or the William D. Ford Federal Direct Loan program. Under current law, an otherwise qualified full-time teacher must complete five consecutive years of service to be eligible for the teacher loan forgiveness program. This bill permits a teacher who completes five full-time years of non-consecutive service to be eligible for loan forgiveness if the teacher was a qualified military spouse during a break in teaching service. A qualified military spouse is an individual who: (1) is a highly-qualified teacher at a high-need school, (2) is the spouse of a servicemember, (3) experienced a break in teaching service to relocate with servicemember spouse pursuant to military orders, and (4) resumed teaching the following year.