Abstract. The λµμ-calculus, defined by Curien and Herbelin [7], is a variant of the λµ-calculus that exhibits symmetries such as term/context and call-by-name/call-by-value. Since it is a symmetric, and hence a non-deterministic calculus, usual proof techniques of normalization needs some adjustments to be made to work in this setting. Here we prove the strong normalization (SN) of simply typed λµμ-calculus with explicit substitutions. For that purpose, we first prove SN of simply typed λµμ-calculus (by a variant of the reducibility technique from Barbanera and Berardi [2]), then we formalize a proof technique of SN via PSN (preservation of strong normalization), and we prove PSN by the perpetuality technique, as formalized by Bonelli [5].