St Dionysius' Church, Market Harborough is a Grade I listed parish church in the Church of England in Market Harborough, Leicestershire.
The earliest parts of the church date from the 13th century, with most features dating from 14th and 15th centuries. Part of the tower was destroyed in a storm in 1735 and the replacement was several feet shorter. Restoration work was carried out in 1857 when the pews of 1751 were cut down in height to about 3 ft and the organ moved from the west gallery to a specially constructed recess. The church reopened on 8 January 1858. In 1887 the chancel and south aisle were re-roofed. In 1953 the nave roof was replaced. This was required due to Deathwatch Beetle damage.
The organ was built by G.M. Holdich of London and opened on 14 July 1844. The organ was removed in 1857 by the same builder to receive repairs and was improved with an additional octave of pedals. When returned to the church it was placed on the north side of the chancel in a new recess built specially for it.
It was replaced in 1877 with a new instrument by J Porritt of Leicester. This was inaugurated on 9 August 1877. Modifications were made in 1914. A specification of the organ can be found on the National Pipe Organ Register.
There are ten bells in the belfry. Eight of the bells were recast in 1901 and two new bells were added in 1990.