The aim of the study was to identify the specific features of meadow sward formation under different restoration methods on arable lands of the Right-Bank Forest-Steppe of Ukraine, considering species composition, life span, family structure, fertilization systems, and mowing regimes. Field studies were conducted on gray forest soils in the northern Forest-Steppe of Ukraine (Chabany, Kyiv region). A long-term field experiment compared spontaneous fallow restoration, improved fallow with overseeding of seven native grass species collected from a virgin meadow, and restoration of degraded old-sown grasslands by overseeding a grass mixture (smooth brome Bromopsis inermis + meadow fescue Festuca pratensis) or four legume-grass mixtures including alfalfa (Medicago sativa), red clover (Trifolium pratense), white clover (Trifolium repens), or Ukrainian bird’s-foot trefoil (Lotus ucrainicus). Treatments were evaluated under three fertilization backgrounds and two mowing regimes. Species composition was assessed using geobotanical surveys. In the ninth year of succession, fallow phytocenoses were dominated by perennial non-sown grasses, accounting for 59-82% of the vegetation, while forbs represented 18-38%. Wood small-reed (Calamagrostis epigeios) was the dominant wild grass species. Spontaneous fallow supported up to 37 herbaceous species, whereas overseeding native grasses increased diversity to 45 species. The occurrence of species such as Festuca valesiaca reflected the increasing contribution of characteristic meadow species to the developing phytocenosis. Nitrogen fertilization (N₁₄₀) or complete mineral fertilization (N₁₄₀P₆₀K₁₂₀) increased the proportion of grasses by 10-14%. Restoration through overseeding cultivated grasses and legumes reduced the number of wild species to 21-31 but rapidly improved forage quality. During the first three years, the swards were dominated by the introduced cultivated species. Overseeding smooth brome and meadow fescue resulted in a smooth brome-dominated community by the third year. In legume–grass mixtures, legumes acted as codominants with the grasses. Alfalfa and Ukrainian bird’s-foot trefoil remained stable in the swards, maintaining a 33-50% share for three years, whereas red and white clovers persisted only during the first two years with a 36-53% share. These results demonstrate that native-species restoration promotes biodiversity and ecological stability, while cultivated grass–legume mixtures provide rapid establishment of productive forage swards.