James Bolivar Manson (26 June 1879 in London – 3 July 1945 in London) was an artist and worked at the Tate gallery for 25 years, being its Director 1930–1938. In the Tate's own evaluation he was the "least successful" of their Directors. His time there was frustrated by his stymied ambition as a painter and he declined into alcoholism, culminating in a drunken outburst at an official dinner in Paris. Although his art policies were more advanced than previously at the Tate and embraced Impressionism, he stopped short of accepting newer artistic movements like Surrealism and German Expressionism, thus earning the scorn of critics such as Douglas Cooper. He retired on the grounds of ill health and resumed his career as a flower painter until his death.