The Reverend David Rees (14 November 1801– 31 March 1869) was a Welsh Congregational minister of Capel Als chapel Llanelli, Carmarthenshire, and an editor of a radical Welsh language Nonconformist periodical titled Y Diwygiwr (The Reformer). Known as 'Y Cynhyrfwr' ('The Agitator'), he held radical political views and opposed the relationship between the Established Church and the state.