The present study is based on the genus Cotesia Cameron,1891 collected from Khuzestan Province in the Southwestern part of Iran during 2016–2017. Nine species (+200 specimens) of the genus Cotesia were collected and identified. We recognised three new species, which we describe and illustrate here: Cotesia elongata Zargar & Gupta sp. nov., C. khuzestanesis Zargar & Gupta sp. nov. and C. zagrosensis Zargar & Gupta sp. nov. Two species are recorded for the first time from Iran: Cotesia cynthiae (Nixon, 1974) and C. glabrata (Telenga, 1955). A faunistic list with species distribution in Iran, a modified key to include the new species and brief diagnoses for the new records from Iran are provided.