St. Catherine's Oratory, also known as the Pepperpot, is a medieval lighthouse on St. Catherine's Down near the southern coast of the Isle of Wight. It was built by Lord of Chale Walter de Godeton as an act of penance for plundering wine from the wreck of St. Marie of Bayonne in Chale Bay on April 20, 1313 AD.

The lighthouse is a stone structure 4 stories high. It is octagonal on the outside and four-sided on the inside. It originally was on the west side of an adjacent building. The remnants of three other walls are visible at the site.

de Godeton was put on trial in Southampton before an Island jury for the theft of the wine, and fined 287.5 marks on February 27, 1314. However, de Godeton was also tried for the theft in Church courts as well, since the wine was headed for the monastery of Livers in Picardy. The Church threatened to excommunicate de Godeton unless he built a lighthouse near Chale Bay.

In the 18th century Sir Richard Worsley of Appuldurcombe House bolstered the structure by adding 4 large buttresses to prevent its collapse.