Abstract. In this work we present proof terms for a Gentzen sequent style presentation of HOL. Existing implementations of proof terms for HOL are natural deduction style systems. Sequent style proof terms have many advantages over natural deduction style proof terms. For example, we can translate proof terms directly into tactics, which we can execute at the tactic level of HOL implementations. We describe several applications of our work, such as an implementation of theory interpretation, and an approach to optimising proof terms by rewriting. 1