AbstractAs a large group of Hemiptera, aphids are distributed worldwide, and most of them are pests. In China, aphid fauna of many areas, such as northwestern China, have been systemically studied. Hong Kong is an exception. Based on literature and specimens from the British Natural History Museum and the Institute of Zoology of the Chinese Academy of Sciences, we studied the species diversity of aphids in Hong Kong. The results showed that 70 species, 44 genera and 7 families of aphids are found in Hong Kong, accounting for 6.83%, 16.60%, and 53.85% of known aphid species, genera and families in China, respectively. There are six endemic species in Hong Kong. Hong Kong belongs to the Oriental faunal region, and Hong Kong’s aphid species mainly consist of Oriental, Palaearctic-Oriental, and Australian-Oriental components. The host plants of aphids include 58 genera in 30 families, among which Gramineae, Moraceae, and Lauraceae have the highest aphid diversity. Of the aphids, Aphididae has the most host plants, while Hormaphididae and Drepanosiphidae rank second and the third respectively. In general, although Hong Kong covers a small area of China, its diverse landforms, suitable climate and abundant vegetation provide many niches for aphids, which results in the rich diversity of aphids.