Background: Research on biosecurity is important as New Zealand's agricultural export-driven economy is susceptible to biosecurity threats. Because New Zealand is reliant on the primary industries to drive its economy, bovine diseases such as foot and mouth could have a devastating effect on the economy. Purpose: Making sure that the general public are aware of the importance of maintaining biosecurity is crucial in order to protect New Zealand's economy, human health, the environment, and social and cultural values. New Zealand Year 9 students' knowledge of biosecurity was gauged as these students represented the next generation of individuals tasked to maintain biosecurity in New Zealand. Design: A qualitative approach using the interpretive mode of inquiry was used to investigate the knowledge about biosecurity with New Zealand Year 9 students. Questionnaires and interviews were the data collection tools. Sample: One hundred and seventy-one students completed a questionnaire that consisted of Likert-type questions and open-ended questions. Nine students were interviewed about their knowledge. Results: The findings showed that New Zealand Year 9 students lacked specific knowledge about unwanted plants, animals and microorganisms. These students saw illicit drug plants as unwanted plants and mainly saw possums as unwanted animals in New Zealand. Their knowledge about unwanted microorganisms in New Zealand was dominated by human-disease-causing microbes. A lack of knowledge of biosecurity issues in New Zealand was seen as the major factor in these students limited understanding of biosecurity. Conclusions: Based on these findings, it can be said that knowledge of an issue is critical in enabling individuals to develop an understanding about biosecurity. Explicit teaching of biosecurity-related curriculum topics could provide New Zealand Year 9 students with an opportunity to develop knowledge about biosecurity in New Zealand.