We evaluated the repellent activity of 12 Apiaceae plant essential oils and their components against male and female adult German cockroaches, Blattella germanica, to find new natural repellents. Of the plant essential oils tested, ajowan (Trachyspermum ammi) and dill (Anethum graveolens) essential oils showed the most potent repellent activity against male and female adult German cockroaches. Of the compounds identified, carvacrol, thymol, and R-(-)-carvone showed >80% repellent activity against male and female adult German cockroaches at 0.2 mg/L air concentration. S-(+)-Carvone, (+)-dihydrocarvone, and terpinen-4-ol showed >70% repellent activity against male and female adult German cockroaches at 0.8 mg/L air concentration. Our results indicated that Apiaceae plant essential oils and their constituent have good potential as natural repellents against adult German cockroaches.