Konstantin Yakovlevich Bulgakov (Russian: Константин Яковлевич Булгаков; 31 December 1782 – 29 October 1835) was a Russian diplomat, privy councillor, and postal administrator. Konstantin Bulgakov served as the Director of the Moscow Post Office. Since 1819 he was the Director of Saint Petersburg Post Office. Bulgakov later became the Director of the Postal Department of the Russian Empire. He and his brother Alexander Bulgakov, Director of the Moscow Post Office, could freely correspond with each other because both were the top officers of the Russian Postal Service.