Dafydd is a Welsh masculine given name, related to David, and more rarely a surname. People so named include:

• Dafydd ab Edmwnd (fl. c. 1450–97), Welsh poet
• Dafydd ab Ieuan or David Holbache (died 1422/3), Welsh politician
• Dafydd ab Owain Gwynedd (c. 1145-1203), Prince of Gwynedd
• Dafydd ap Gruffydd (1238–1283), Prince of Wales
  • Dafydd Goch, said to be the illegitimate son of Dafydd ap Gruffydd
• Dafydd ap Gwilym (c. 1315/1320–c. 1350/1370), Welsh poet
• Dafydd ap Llywelyn (1215–1246), Prince of Gwynedd and first Prince of Wales
  • Dafydd ap Dafydd ap Llywelyn (born between 1240 and 1246-?), illegitimate son of Dafydd ap Llywelyn
• Dafydd Bach ap Madog Wladaidd (fl. 1340-1390), Welsh poet
• Dafydd Benfras (fl. 1230-1260), Welsh court poet
• Dafydd Ddu o Hiraddug (died 1371), Welsh poet, grammarian and cleric
• Dafydd Gam (1380-1415), Welsh soldier and nobleman who died at the Battle of Agincourt
• Dafydd Gorlech (c. 1410-c. 1490), Welsh poet
• Dafydd Llwyd ap Llywelyn ap Gruffudd (Dafydd Llwyd o Fathafarn) (fl. c.1400–c.1490), Welsh poet
• Dafydd Nanmor (fl. 1450–1490), Welsh poet