Appin Road is a New South Wales secondary highway linking Campbelltown and Sydney's western suburbs with Wollongong.

It is named after Appin, which lies on its path.

Appin Road commences at the intersection with Oxley Street and Narellan Road in Campbelltown and heads in a southerly direction as a four-lane, dual-carriageway road, narrowing to a two-lane, single carriageway road at Rosemeadow, to Appin, before continuing in a south-easterly direction to the interchange with Princes Motorway at Bulli Tops, in the Illawarra region just north of Bulli.

177 was declared along this road on 8 August 1928, from the intersection with Narellan Road in Campbelltown, via Appin to the intersection with Princes Highway near the top of Bull Pass (and continuing north along Campbelltown Road to the intersection with Hume Highway at Crossroads);[2] with the passing of the Main Roads (Amendment) Act of 1929[4] to provide for additional declarations of State Highways and Trunk Roads, this was amended to Main Road 177 on 8 April 1929.

With the conversion to the newer alphanumeric system in 2013, this was replaced with route B69.