An insect diversity survey was carried out at Bukit Hampuan Forest Reserve, adjacent to Kinabalu Park in Sabah, Malaysia. The nocturnal insect diversity was very high, with a mean of 113 species recorded from one square metre of light-trapping cloth. Diurnal insects were sampled using sweep nets and fine forceps. A total of 19 Bornean endemic insect species were recorded, comprising 15 moth and four beetle species. A few of the endemic moths are confined to Sabah, namely Buzara saikehi, Cyana saulia and Lyclene mesilaulinea. Forty-two butterfly species were recorded. Endemic insect species sampled from this survey indicate the significance of protecting and conserving this forest reserve. Such findings provide important data to enhance the need and effort in biodiversity conservation. The recent gazettement of Bukit Hampuan Forest Reserve is appropriate, and it is also recommended that Bukit Hampuan Forest Reserve be connected to the adjacent Kinabalu Park, i.e. to gazette the connecting state land area into a forest reserve. Forest fires, illegal hunting for wild animals and orchids, and agricultural activities are among the threats to Bukit Hampuan Forest Reserve which directly affect its insect diversity. To mitigate these threats, it is important to adopt a multi-disciplinary and participatory approach in a smart partnership involving relevant stakeholders and the local communities in monitoring, enforcement and promoting environmental awareness.