The bullet tuna, Auxis rochei, is a commercially significant scombrid in small-scale inshore fisheries in the northeastern Atlantic and western Mediterranean. We hypothesized that the Gulf of Cádiz could serve as a spawning area of bullet tuna. We analysed the gonads and GSI of 428 individuals (23.9–48.7 cm SFL) caught by Portuguese and Spanish traps along the south Atlantic Iberian Peninsula, as well as by Spanish recreational fishery between 2004 and 2021. Larvae of bullet tuna were collected during surveys conducted on the northern shelf of the Gulf of Cádiz in June and August. Bullet tuna landings exhibited high seasonality in the Gulf of Cádiz, peaking during the warmest months, notably from August to October. Analysis of maturity data, monthly GSI variations, larvae distribution, and landings indicate that bullet tuna is reproductively active in the Gulf of Cádiz, particularly in July and August. A more comprehensive understanding of the reproductive behaviour of bullet tuna in this region is essential to confirm its reproductive success and to study recruitment mechanisms further.