RSPB Minsmere is a nature reserve owned and managed by the Royal Society for the Protection of Birds (RSPB) at Minsmere, Suffolk. The 1,000-hectare (2,500-acre) site has been managed by the RSPB since 1947 and covers areas of reed bed, lowland heath, acid grassland, wet grassland, woodland and shingle vegetation. It lies within the Suffolk Coast and Heaths Area of Outstanding Natural Beauty and the Suffolk Heritage Coast area. It is conserved as a Site of Special Scientific Interest, Special Area of Conservation, Special Protection Area and Ramsar site.
The nature reserve is managed primarily for bird conservation, particularly through control and improvement of wetland, heath and grassland habitats, with particular emphasis on encouraging nationally uncommon breeding species such as the bittern, stone-curlew, marsh harrier, nightjar and nightingale. The diversity of habitats has also led to a wide variety of other animals and plants being recorded on the site.
Before becoming a nature reserve, the area was the site of an ancient abbey and a Tudor artillery battery. The marshes were reclaimed as farmland in the 19th century, but were re-flooded during World War II as a protection against possible invasion.