Four species of green hairstreak butterflies, namely Ahlbergia ferrea, A. tricaudata, A. frivaldszkyi, and A. leei, belonging to the genus Ahlbergia Bryk, 1946 (Papilionidea: Lycaenidae), are examined in Korea. It was discovered that Ahlbergia frivaldszkyi, which was previously incorrectly reported in Korea, is actually A. leei. We report two species, A. frivaldszkyi and A. tricaudata as new additions to the Korean fauna. Detailed diagnoses of these four species are provided, including descriptions of both male and female genitalia, along with a key for identifying the four species found in Korea.