This study was conducted to investigate the effects of nanoemulsions prepared with various concentrations of olive oil on the sensory, chemical and microbiological quality of rainbow trout fillets. The results showed that the shelf life of rainbow trout fillets were determined as 10 days for the control, 12 days for tween 80 group, 14 days for the 15% olive oil nanoemulsion group (O15) and 16 days for both 30% (O30) and 45% olive oil nanoemulsion groups (O45). It was determined that the use of olive oil suppressed the fish smell and improved the organoleptic quality of fish fillets, extending shelf life. Best sensory results were obtained from O30 and O45 treatment groups. The use of nanoemulsion had a positive effect on the biochemical parameters (TVB-N, PV, FFA, TBARs and pH), as well as inhibiting bacterial growth compared to the control group. Among nanoemulsion groups, the lowest bacteria content was found in O45 group. As a result, O30 and O45 treatment groups can be recommended for the preservation of fish fillets.