Blythburgh is a village and civil parish in the Suffolk Coastal district of the English county of Suffolk. It is west of Southwold and south-east of Halesworth and lies on the River Blyth. The A12 road runs through the village which is split either side of the road. At the 2011 census the population of the parish was 297. The parish includes the hamlets of Bulcamp and Hinton.
Blythburgh is best known for its church, Holy Trinity, known as the Cathedral of the Marshes. The church has been flood-lit since the 1960s and is a landmark for travellers on the A12. The village is the site of Blythburgh Priory which was founded by Augustine monks from St Osyth's Priory in Essex in the 12th century. The priory was suppressed in 1537 and ruins remain at the site.
The village is in the area of the Suffolk Coast and Heaths Area of Outstanding Natural Beauty in the area known as the Suffolk Sandlings. It is close to the Suffolk heritage coast located close to an area marshland and mud-flats along the River Blyth which were flooded in 1940 as part of British anti-invasion preparations at the start of the Second World War.