This dataset provides aggregated vegetation cover data for functional plant groups recorded in the same 2 × 2 m quadrats used for species-level vegetation surveys. For each quadrat, total vegetation cover and the proportional cover of predefined functional groups were visually estimated during a single survey per plot, typically conducted in May or June. Vegetation and functional group data were collected simultaneously. Recorded cover variables (in %) include total herb layer cover, grasses, forbs, legumes, bare ground, cryptogams, and litter layer. Estimates are based on field assessments and represent overall percentage cover per quadrat. The dataset further includes sub-transect identifiers, date, and observer information. These data enable analyses of vegetation structure and functional composition and can be directly linked to species-level, vegetation height, flower cover, soil, and pollinator datasets from the same study sites. Data were collected at multiple grassland sites across Northern, Central, and Southern Germany in 2022 and 2023, with site coordinates reported at two-decimal precision (blurred for privacy).).