Marumba jankowskii is a species of moth of the family Sphingidae. It is known from south-eastern Russian Far East, north-eastern China, North Korea, South Korea and Japan. The wingspan is 68–80 mm. It is similar to Marumba maackii, but the hindwing upperside costal and distal areas are not yellow. Adults are on wing from early June to late August in Korea. The larvae feed on Tilia species, including Tilia mandshurica.