David Robb Campbell (1874 or 1875 – 14 January 1934), often known as Davy Campbell, was a trade unionist based in Belfast. Campbell grew up in a Protestant family in Belfast. He became a socialist, joining the Independent Labour Party (ILP) and the Belfast Socialist Society. He became increasingly at odds with William Walker, the leading member of the Belfast Labour Representation Committee as, unlike Walker, Campbell supported Irish independence and preferred to work with the Dublin-based labour movement, rather than the London-based one. As a result, in 1910, Campbell joined James Connolly's Socialist Party of Ireland, and when Connolly moved to Belfast in 1911, the two worked closely together.