Justine Lacoste-Beaubien (October 1, 1877 – January 17, 1967) was one of the founders of the children's hospital Sainte-Justine Hospital.
Born in Montreal, the daughter of Alexandre Lacoste and Marie-Louise Globensky, she married Louis de Gaspé-Beaubien, son of Hon. Louis Beaubien, in 1899. Her maternal great-grandfather was born in Berlin to a family of Polish origin.
In 1934 Lacoste-Beaubien was made an Officer of the Order of the British Empire "for services for sick and crippled children; in founding and extending the St. Justine Hospital".