Achaemenothrombium khashayarshahi Noei sp. nov. (Acari: Achaemenothrombiidae) is described and illustrated from larvae ectoparasitic on Lepidoptera from Khorasan Razavi and South Khorasan provinces, Iran. This is the fifth larval species of the genus, this far known only from Iran. A key to the larval species of Achaemenothrombium is presented.