William Thomas (1785 – November 5, 1863) was an English-born merchant and politician.
Thomas was active in the effort to earn Newfoundland its own parliament and was appointed to the committee "to petition his majesty for a legislature."
He also was active in the concerns of the poor, serving on numerous committees to help improve their condition, including work on a commission to assign work to those on welfare.
He came to Newfoundland in 1801 and entered business in partnership with his brother Henry.
Thomas was named to the colony's three-person Executive Council in 1833, working on early efforts to establish self-governance for Newfoundland.