Head lice (Pediculus humanus capitis) infestations are a public health concern. The insecticidal properties of the Australian native plant Kunzea ambigua (commonly known as tick bush) have been documented. In this study, we tested activity of kunzea oil (KO) against head lice through in vitro bioassays. Head lice were exposed to filter paper treated with either KO, as either a 5 or 100% oil, or commercial formulations containing either permethrin or tea tree oil (TTO) for 120 min. Head lice exposure to KO, both as a 5 and 100% solution oil, resulted in 100% mortality within 120 min with a mean survival times of 17·1 and 34·8 min, respectively. There was no significant difference between the mean mortality of head lice exposed to 5% KO (17·1 ± 1·0; 95% CI: 115·2–19·0) and 5% TTO (21·2 ± 1·9; 95% CI: 17·4–25·1). This study revealed, for the first time, that KO holds great potential as an effective alternative to current active ingredients contained within commercial pediculicide formulations.