New Hampshire Route 124 (abbreviated NH 124) is a 28.05-mile-long (45.14 km) east–west highway in southern New Hampshire, United States. It runs from Marlborough to the Massachusetts border.
The western terminus of NH 124 is in Marlborough at New Hampshire Route 101. The road continues through Marlborough, a short section of Troy and enters the northwestern part of Jaffrey. The road skirts the southern slopes of Mount Monadnock, across Jaffrey, and into Sharon. In Sharon there is an historic marker on the northern side of the road marking the site of a gate that once collected tolls for the 3rd New Hampshire Turnpike, which followed much of the present-day route of NH 124. The road enters New Ipswich and continues through that town.
The eastern terminus of NH 124 is at the Massachusetts state line in Mason. The road continues into Massachusetts as an unnumbered local road in the town of Townsend.