Sussex County Cricket Club is the oldest of eighteen first-class county clubs within the domestic cricket structure of England and Wales. It represents the historic county of Sussex. Its limited overs team is called the Sussex Sharks. The club was founded in 1839 as a successor to the various Sussex county cricket teams, including the old Brighton Cricket Club, which had been representative of the county of Sussex as a whole since the 1720s. The club has always held first-class status. Sussex have competed in the County Championship since the official start of the competition in 1890 and have played in every top-level domestic cricket competition in England.

Inter-county cricket matches have been played since the early 18th century, involving teams that are representative of the historic counties of England and Wales. Since the late 19th century, there have been two county championship competitions played at different levels: the County Championship, a first-class competition which involves eighteen first-class county clubs among which seventeen are English and one is from Wales; and the National Counties Championship, which involves nineteen English county clubs and one club that represents several Welsh counties.