Helen Galloway McNicoll (1879–1915) was a Canadian impressionist painter.

She was born in Toronto to parents David McNicoll and Emily Pashley.McNicoll became deaf in childhood as the result of scarlet fever, so she learnt early on to develop other skills like lip-reading, playing the piano and developing her talents as an artist. She attended the Art Association of Montreal, studying under William Brymner from 1899. In 1902 she moved to England to study in London at the Slade School under Philip Wilson Steer. At Slade, students were encouraged to paint en plein air. Later she studied in St Ives, Cornwall with Algernon Talmadge. This is where she met Dorothea Sharp, a fellow artist who became a lifelong friend. They traveled together and shared studio space, as well as posed for each other's paintings.

A member of the Royal Society of British Artists and an associate of the Royal Canadian Academy of Arts,she died in Swanage, Dorset, where she had made her home, aged only thirty six. An obituary described her as "one of the most profoundly original and technically accomplished of Canadian artists".