The current study aimed to evaluate the effect of fishmeal (FM)replacement with insect meal from Hermetia illucens in the diet of Sparus aurata, farmed inshore, on microbiota composition. Two isolipidic (18%, as fed) and isoproteic (42% as fed) diets were tested at farm scale: a control diet with no insect meal (FM), and an experimental diet (HIM) with 11% of insect meal in substitution to FM. High-throughput 16S rRNA gene amplicon sequencing was utilized to characterize the gut microbial community profiles. The results indicated that dietary inclusion of insect meal, as an alternative animal protein source, positively affected seabream gut microbiota, by increasing the amount of beneficial genera.