Constantine Diogenes (; died 1032) was a prominent Byzantine general of the early 11th century, active in the Balkans. He served with distinction in the final stages of the Byzantine conquest of Bulgaria under Emperor Basil II, and occupied high commands in the Balkans until his arrest in 1029, as the result of his participation in a conspiracy against Emperor Romanos III Argyros. Imprisoned and forced to enter a monastery, he committed suicide in 1032 during an inquest on a further conspiracy. He was the father of Emperor Romanos IV Diogenes.