The purpose of this study was to describe the structure and composition of Diptera in Moroccan vineyard, using wet-traps sampling technique throughout 2017. The study focused on five varieties within Loudaya vineyard (west region of Marrakech, Morocco). Eleven different fly species were identified belonging to 10 families, Ceratitis capitata, Drosophilla suzukii and Thaumatiya notata were the most abundant species and first time behaviourally dominant flies species. In addition, more flies were captured in the local varieties (10 579 individuals) than in the introduced ones (966). Moreover, a significant difference was observed in fly richness, evenness and diversity between varieties. Fly community structure in Loudaya showed a clear seasonal dynamics, which richness, abundance, diversity and evenness were significantly (P < 0.001) dissimilar among months. Furthermore, Diptera species were positively influenced by humidity and rainfall. Richness (expected by sample-based rarefaction) and diversity peaked in the middle of vineyard phenology, corresponding to mid-spring to late-summer in all varieties. Fly species occurrence and seasonal climatic variation in Loudaya vineyard might be among various ecological factors such as habitat distribution, climate and the availability of resources. Taking into account the periods of fly abundance, the survey could give relevant indications on new approaches to integrated pest management (IPM) in Moroccan vineyards, particularly in the Loudaya region.