Gerald Cassidy was an early 20th-century artist, muralist and designer who lived in Santa Fe, New Mexico.

Cassidy was born in Covington, Kentucky on November 10, 1869 as Ira Dymond Gerald Cassidy. He studied art at the Institute of Mechanical Arts under Frank Duveneck, and the Art Students League in New York.

At the same moment that Cassidy was first finding success he contracted a life-threatening case of pneumonia and was moved to a sanitarium in Albuquerque in 1890. It was here that he first saw the people and places of the American Southwest, the subject matter that he would dedicate his entire life's work to after this point. His first work using American Indian and Western subjects was heavily art deco, and a deco edge would remain in his work even as it developed into a more solidly realist style.

Cassidy moved from Albuquerque to Denver to work as a lithographer. In 1912 he moved and settled in Santa Fe, New Mexico where he met Edgar L. Hewett, founding director of the Museum of New Mexico. Hewett commissioned him to paint his first mural at the Panama-California International Exposition. He painted the Navajo in works that were primarily transferred to postcards or posters. At the 1915 Panama-California International Exposition in San Diego Cassidy was awarded the gold medal for his murals, the largest award he would win in his lifetime. Cassidy also created the mural Dawn of the West and the Parfet Park memorial in Golden, Colorado, where he was an honorary member of the Golden Kiwanis Club.

During the mid-twenties Cassidy traveled in Europe, and his pieces were well thought of by the European public. Pablo Picasso chose one of Cassidy's pieces from a show for inclusion in the Luxembourg Palace in Paris.

He died on February 12, 1934 as a result of turpentine and carbon monoxide poisoning from a newly installed natural gas heater in his studio while working on a mural art project for the dome of the federal building at Santa Fe.