Arklow (Irish: An tInbhear Mór) is a barony in County Wicklow, Ireland.

Arklow barony derives its name from the town of Arklow (from Old Norse Arnkells Lág, "Arnkell's land". The Irish name means "large estuary.")

Arklow barony is located in southeastern County Wicklow, opening onto the Irish Sea, containing Wicklow Head, Mizen Head and Arklow Head.

The Uí Garrchon in the north and the Uí Enechglaiss in the south are noted in Arklow barony from about the 7th century. This was part of Ó Broin country after the 12th century, referred to as Crioch Branach.

Below is a list of settlements in Arklow barony:

• Arklow
• Glenealy (southern part)
• Redcross