Agnes Martin (March 22, 1912 – December 16, 2004) was a Canadian-American painter, often referred to as a minimalist, although she considered herself an abstract expressionist.

She was born in Macklin, Saskatchewan and moved to the United States in 1931, becoming a citizen in 1950. She studied art at Columbia University and then later at the University of New Mexico. Her work is most closely associated with Taos, New Mexico, although she moved to New York City after being discovered by the gallery owner Betty Parsons in 1957. Disillusioned with the art scene in New York, she returned to New Mexico in 1967 and established herself as a hermit at the foot of the Sangre de Cristo Mountains.

The bulk of her work is composed of square grids. While minimalist in form, these paintings were quite different in spirit from those of her minimalist counterparts; she shied away from intellectualism, favoring the personal and spiritual. Many of her grids represent Taoist reflections. Because of her work's added spiritual dimension, which became more and more dominant after 1967, she preferred to be classified as an abstract expressionist. She consciously distanced herself from the social life and publicity events that brought other artists into the public eye. When she died at age 92, she was said to have not read a newspaper for the last 50 years. The book dedicated to the exhibition of her work in New York at The Drawing Center in 2005: 3 X Abstraction (Yale University Press) analyses the spiritual dimension in Martin's work.

She worked only in black, white, and brown before moving to New Mexico. During this time, she introduced light pastel washes to her grids, colors that shimmered in the changing light.