Georges William Thornley (1857–1935) was a French painter and printmaker.

A student of the French landscape painter Eugène Ciceri and Edmond Yon, Thornley became a successful artist remembered for his seascapes from Normandy and his landscapes from the French and Italian Rivieras. He was the son of a Welsh immigrant Morgan Thornley.

He also was a talented watercolorist, engraver, and lithographer. His lithographs after the works of Corot, Pissarro, Degas and Puvis de Chavannes were acclaimed by his peers and awarded at the Salon de Paris.

His paintings were exhibited beginning in 1878. He won the Mention of Honor in 1881 and a Third Class medal in 1888. Thornley embraced the Impressionist movement early in his career, which brought him much success.

His style characteristically has bold brushwork and thick "impasto." It recreates the "impression of a panorama", capturing the fleeting moment in its inner light and color. This open landscape is an example of what the artist excelled at: successful color effects which are highly decorative but stay true to nature.