Glendalough is a former monastic settlement in County Wicklow, Ireland.

Glendalough may also refer to:

• The former Diocese of Glendalough
  • The current Diocese of Dublin and Glendalough
• Glendalough, Rosewood, a heritage-listed villa in Rosewood, City of Ipswich, Queensland, Australia
• Glendalough State Park, Minnesota, US
• Glendalough, Western Australia, a suburb of Perth
  • Electoral district of Glendalough
  • Glendalough railway station
• Bodleian Library, MS Rawlinson B 502, sometimes called The Book of Glendalough