Adolphe Smith Headingley (1846–1924) was a British left-wing political writer. Half-French, Smith Headingley was a member of the First International and took part in the Paris Commune. In 1877–78, he wrote and published the magazine series Street Life in London with photographer John Thomson, to raise awareness of the plight of the city's poor. Smith Headingley played a key role in organising the 1882 International Trades Union Congress and served as an interpreter at successive conferences from 1886 to 1905. It was Smith Headingley that, in the 1890s, popularised the singing of the socialist anthem "The Red Flag" to the tune of "O Tannenbaum".