What is an Interest Only Loan? An Interest-Only loan is a home loan program where you have an option to make "interest-only" payments for a defined period of the loan. The term "interest-only" does not mean not mean a consumer will never have to repay the principal amount of the loan. Usually there is a term in which you will pay only interest. After that term, you would then have to pay both interest and principle. Interest only loans generally use a variable interest rate.