Like other towns and villages Barnoldswick's origins can be traced back to Saxon times. Special mention is made in the 1086 Doomsday Survey and was described as a hamlet named: Bernulfswuic. The name is said to be derived from a man called "Bernulf".
Following the Norman Conquest, Barnoldswick was designated as a venue to host a Monastery. In 1147 twelve Cisterian Monks and ten Lay Brothers arrived from Fountains Abbey to begin the project. The monks did not have a happy time here in Barnoldswick. Crops would reluctantly grow, they interfered with the local clergy's running of their church and robbers frequently made life a misery for them. After about 6 years the Monks left Barnoldswick, their Monastery unfinished, and began work on Kirkstall Abbey in Leeds.
The Monks did however return 10 years later. Still wanting to complete a church, they set about building what is now known as St.Mary-le-Gill church on the outskirts of Barnoldswick.
Barnoldswick remained a small village for hundreds of years. The local Pennine moorland was a source of grazing sheep. This in turn led to the beginning of cottage textile industries. By 1880 there were 5 water-wheels in operation and 2 small mills powered by steam engines. The industrial revolution encouraged more growth as Barnoldswick became an important cotton town. Bancroft Mill Engine Museum in Barnoldswick is open to the public on certain days. It preserves one of the few remaining steam-driven mill engines.