Arthurs Seat is a hill and locality on the Mornington Peninsula, within the Shire of Mornington Peninsula, about 75 km south east of Melbourne, Australia. The Aboriginal Boonwurrung name for the hill is Wonga.
It is a major tourist attraction, owing to its natural bushland, sweeping views and man-made attractions. The hill rises to 314 m (1,030 ft) above sea level.
The underlying rocks are Devonian granite, bounded to the west by the Selwyn Fault. The vegetation consists of dry open forest of mixed eucalypt species, which was extensively burnt during a bushfire in 1973 and again in 1997. The indigenous vegetation on the north-west face has been heavily infested with noxious weed and much of the natural vegetation has been cleared away, although several large stands still remain.