The Lam Brook is a stream in the West Country of England, which rises in a number of springs on the southern end of the Cotswold Hills and runs in a generally southerly direction for approximately 2.5 miles (4.0 km) before joining the river Avon at Lambridge in Bath.

The waters are relatively clean and support a variety of wildlife including the rare white-clawed crayfish.

Streams from a number of springs issuing from the southern end of the Cotswold Hills at Lansdown Hill in Somerset, and Toghill and Cold Ashton in South Gloucestershire converge at Ashcombe Farm near Langridge, Somerset.

[1] Lam Brook is mentioned in an Anglo-Saxon charter as forming part of the boundaries of the village of Charlcombe.

[5] [6] Toad patrol volunteer Helen Hobbs received an award from the International Fund for Animal Welfare in 2010 for her work in saving around 4,500 amphibians.