A checklist of onion insect pests is given herein with 149 species of eleven arthropod orders, viz., Coleoptera, Collembola, Dermaptera, Diptera, Orthoptera, Hemiptera, Hymenoptera, Thysanoptera and Lepidoptera and two of Acarina, such as Sarcoptiformes and Trombidiformes. This comprises 49 families of which 46 are insect and three of Acarina. Insect family, Noctuidae includes maximum genera (16), species (27) followed by the Aphididae (8), Agromyzidae (8), Thripidae (7), Anthomyiidae (6), Syrphidae, (6), Acarididae (6), Pyralidae (5), Scarabaeidae (5), Tetranychidae (4), Muscidae (4), Fanniidae (4), Nitidulidae (3), Onychiuridae (3), Eriophyidae (2), and Simunthridae (1) are others observed. Diversity analysis revealed that foliage feeders are the dominant (69.1%) comprising of sucking pests (aphids and thrips), defoliators (cutworms and leaf eating caterpillars) and leaf miners. Bulb feeders account about 18.8% (flies, beetles, weevils, moths and mites), and root feeders represent 8.7%.