Roydon Common is a 194.9-hectare (482-acre) biological Site of Special Scientific Interest east of King's Lynn in Norfolk, England.

There are rare plants, birds and insects, including the black darter dragonfly.

The common also supports some uncommon dragonfly species such as the broad-bodied chaser.

Many species of flowers grow in grassy clearings on the drier ground, which attract butterflies such as green and purple hairstreaks and brown argus.

There is access by footpaths including one from Pott Row which runs along the southern boundary.