Sethna is a (Parsi-)Gujarati surname meaning "pertaining to (-na) the ombudsman/broker/administrator/supervisor(seth-)", and may refer to:
Adi M. Sethna, Indian general Beheruz Sethna, academic Homi Sethna, chemical engineer Kaikhosru Dadhaboy (K. D.) Sethna, poet, philosopher and cultural critic Pheroze Sethna, Indian politician