The objective of this study was to quantify the impact of peatland restoration on Diptera assemblages across multiple organizational levels (taxon, size class, trophic group) and to determine the environmental variables that affected the composition of assemblages among abandoned-mined, restored and natural sites of three bogs. More than 22,000 individuals representing 716 species were collected using pan traps, sweeping and Malaise traps. Results from NMDS ordinations and MRPP comparisons showed that analyses based on ecological traits (size and trophic groups) provided different insights into the recovery of mined bogs after restoration than did those based on taxonomic analyses. Ordination of all Brachycera species did not reveal any differences in composition between treatments, suggesting high resilience to disturbance. However, assemblages collected in different treatment types differed both functionally and in the distribution of the small size-class (< 5 mm). The restored and abandoned treatments were not significantly different from one another in trophic composition, but both differed from natural sites. However, diversity estimates of the restored treatment indicated successful recolonization by predators and saprophages. Assemblages of small size species in restored treatments were intermediate to those in the natural and abandoned treatments. Substrate quality and vegetation cover are important factors influencing species and trophic composition among the three treatment types, especially the coverage of bare peat, Sphagnum mosses and ericaceous shrubs. Brachycera responded positively to peatland restoration, although seven years were not sufficient for full recovery of small size species or overall trophic structure that characterize a natural bog.