Banagher is a town in Republic of Ireland, located in the midlands, on the western edge of County Offaly in the province of Leinster, on the banks of the River Shannon. The name Banagher comes from its Irish name, which translates to English as "the place of the pointed rocks on the Shannon".

Banagher was a town of 3,000 people at the height of its economic growth in the mid-19th century. As of 2016, the population was over 1,700. Banagher was historically an important strategic location on the River Shannon and was one of the few crossing points between the provinces of Leinster and Connacht. It thus became a natural focus for a number of historical buildings, including a 19th-century Martello Tower and a number of castles around the town, which were built in the 14th and 15th centuries.

The town used to be the focus of thriving river business and was an important stop on the Dublin to Limerick navigation. It supported a number of industries, including a maltings and distillery, which are now defunct. Tourism has supplanted this to a certain extent with a modern marina providing support for river cruisers and watersports facilities and the town is an angling centre, with particular attraction for pike anglers. Banagher is the centre of the Shannon Callows, grassy meadows which flood in winter and provide living space for waterfowl.