St Benet Sherehog, additionally dedicated to St Osyth, was a medieval parish church built before the year 1111, on a site now occupied by No 1 Poultry in Cordwainer Ward, in what was then the wool-dealing district of the City of London. A shere hog is a castrated ram after its first shearing.
The church was originally dedicated to St Osyth. Sise Lane in the parish uses a corrupted form of the saint's.name.
The patronage of the church belonged to the monastery of St Mary Overy until the Dissolution, when it passed to the Crown.
Matthew Griffith chaplain to Charles I was rector from 1640 until 1642, when he was removed from the post and imprisoned after preaching a sermon entitled "A Pathetical Persuasion to Pray for Publick Peace" in St Paul's Cathedral.
St Benet's was one of the 86 parish churches destroyed in the Great Fire of London, and it was not selected to be rebuilt when the 1670 Act of Parliament became law. The parish was united to that of St Stephen Walbrook in the same year, but continued to be represented by its own churchwarden. In 1685, a church report judged the unification a success. Nearly two hundred years later, however, this arrangement was still capable of causing tension. Some of its parish records survive, and have been collated.
The site of the church was used as a burial-ground for the united parishes until closed by an act of parliament in 1853. It was excavated between 1994 and 1996, before the current office block was erected.