Gwalchmai or Gwalchmei is a figure in Welsh Arthurian legend known in English as Gawain.

Gwalchmai may also refer to:

Gwalchmai, Anglesey, a village in Anglesey, north Wales Gwalchmai ap Meilyr (12th century), Welsh court poet C.P.D. Gwalchmai, an association football team from Gwalchmai, Anglesey