Robert Wood Williamson (1856 – 12 January 1932) was a British solicitor and anthropologist.
He was educated at private schools and Owens College before studying law at Clement's Inn, where he was prizeman in his law final examinations in 1877.
In 1882 he married Emily Williamson, co-founder of the Royal Society for the Protection of Birds.
From 1903 to 1910 he was a member of the Court of Governors of Victoria University of Manchester.
He was honorary treasurer of the Royal Anthropological Institute (RAI) from 1912 to 1921, member of council for the RAI from 1922 to 1924, vice-president from 1925 to 1927, and again a member of council from 1928 to 1931.