Alexander Dmitrievich Ketov (1914–2011) was a Soviet and Russian theatre artist, set designer, poster artist, and painter who worked in theatrical and decorative art for more than seven decades. He was particularly known for his work in stage design, as well as for portraits and landscapes.

Born in 1914 in Kusa in the Ufa Governorate, Ketov studied at the Art and Pedagogical College in Molotov (now Perm) from 1931 to 1935, specialising in decorative art. He moved to Leningrad in 1935, where he studied in the preparatory classes of the Institute of Painting, Sculpture and Architecture under Isaac Brodsky and at the Institute for Advanced Training of Artists under Mikhail Bershtein. He began exhibiting his work in 1936 and worked at the Kirov Opera and Ballet Theatre and the Opera Studio of the Leningrad Conservatory, where he produced stage decorations, restored Fyodor Chaliapin's costumes, and painted portraits of leading soloists.

During the Siege of Leningrad, Ketov served in an evacuation hospital as an orderly and artist while also working at the newly established Siege Drama Theatre. He produced political posters, including Death to the German Occupiers!, which was displayed as a large panel on Nevsky Prospekt. Few of his works from the siege period have survived.

From 1943, Ketov became closely associated with the Leningrad State Theatre of Musical Comedy, where he worked as a painter and decorator and later headed the decoration workshop. He designed productions including La Périchole, The Wedding in Malinovka, The Circus Princess, The Bird Seller, Silva, The Violet of Montmartre, and Die Fledermaus. Between 1964 and 1966 he served as chief production designer at the Velikoluksky Drama Theatre, before continuing his career as a set designer in the workshops of the Kirov Opera and Ballet Theatre.

Over his career, Ketov created theatrical designs for more than fifty productions. Among the best known were Sadko (1952), based on sketches by Sofya Yunovich, and Prince Igor (1957), based on sketches by Ivan Sevastyanov. As a painter, he was principally known for portraits and landscapes, including portraits of prominent contemporaries such as theatre director Georgy Tovstonogov and actor Kirill Lavrov. Ketov died in Saint Petersburg in 2011, aged 97.