James Foster, junior was an architect active, particularly in Bristol, England, in the late-18th and early-19th centuries.
Foster was the son of James Foster, senior (born around 1748, died 1823), of Bristol, also an architect. Together they worked in partnership in the Bristol-based firm Foster and Son.
After his father's death in 1823 James worked in partnership with his brother, Thomas, and William Ignatius Oakley, the latter's pupil, in the firm Foster and Oakley. From 1819 until 1836 he held office in Bristol as a district surveyor for the city.
James Foster, junior died on 5 January 1836.
Colvin, Howard, A Biographical Dictionary of British Architects 1600-1840, 3rd edition (New Haven and London: Yale University Press, 1995), pp. 372-373.