Joseph Foster Barham I (1729–1789) was the English owner of the Mesopotamia plantation in Westmoreland Parish, Jamaica. Originally Joseph Foster, he took Barham as an additional surname (1750) for Henry Barham M.D., son of Henry Barham F.R.S.
He was the son of Colonel John Foster (1681–1731) of Elim, Jamaica and Egham House, Surrey, and his wife Elizabeth Smith. After John Foster died in 1731, Elizabeth took two more husbands, John Ayscough, like Foster a Jamaica plantation owner, and after Ayscough's death around 1735, Dr. Henry Barham. Barham settled in England as stepfather to the Foster family of five sons and two daughters; he died in 1746. The eldest of the Fosters was Thomas who was Member of Parliament for Dorchester. The other sons were: John, William, Samuel, and Joseph. Of the two daughters, Margaret married Colin Campbell, and Sarah married William Mathew Burt.
Joseph Foster was educated at Eton College, and went on a Grand Tour. The change of his surname to Foster-Barham was a condition of his stepfather Henry Barham's will. It was carried out by Act of Parliament, around 1749. He visited the Mesopotamia estate in Jamaica, and returned to England in 1751. There his religious views were affected by the preaching of John Cennick. He also met Dorothy Vaughan, and they were married in 1754.
Foster Barham settled in Bedford, and was a Moravian from 1756 (as was his brother William, also living in Bedford). An evangelical Christian, his friends included John Newton from 1773, in his days as a curate at Olney.
After his first wife died, in 1781, Foster Barham moved away from the Moravians. He married again, in a Church of England ceremony in 1785; and moved to his new wife's home, Hardwick Hall in Shropshire.
The Mesopotamia plantation dated from the beginning of the 18th century. It passed by marriage from the Stephenson family to the younger Henry Barham; and then to Foster Barham. Ephraim Stephenson died in 1726; his widow Mary shortly married a Mr. Heith, who soon died, and she married Henry Barham in early 1728. She died in 1735.