BACKGROUND: Appropriate case management of suspected malaria in Cambodia is critical given anti-malarial drug resistance in the region. Improving diagnosis and the use of recommended malarial treatments is a challenge in Cambodia where self-treatment and usage of drug cocktails is widespread, a notable difference from malaria treatment seeking in other countries. This qualitative study adds to the limited evidence base on Cambodian practices, aiming to understand the demand-side factors influencing treatment-seeking behaviour, including the types of home treatments, perceptions of cocktail medicines and reasons for diagnostic testing. The findings may help guide intervention design. METHODS: The study used in-depth interviews (IDIs) (N = 16) and focus group discussions (FGDs) (N = 12) with Cambodian adults from malaria-endemic areas who had experienced malaria fever in the previous two weeks. Data were analysed using NVivo software. RESULTS: Findings suggest that Cambodians initially treat suspected malaria at home with home remedies and traditional medicines. When seeking treatment outside the home, respondents frequently reported receiving a cocktail of medicines from trusted providers. Cocktails are perceived as less expensive and more effective than full-course, pre-packaged medicines. Barriers to diagnostic testing include a belief in the ability to self-diagnose based on symptoms, cost and reliance on providers to recommend a test. Factors that facilitate testing include recommendation by trusted providers and a belief that anti-malarial treatment for illnesses other than malaria can be harmful. CONCLUSIONS: Treatment-seeking behaviour for malaria in Cambodia is complex, driven by cultural norms, practicalities and episode-related factors. Effective malaria treatment programmes will benefit from interventions and communication materials that leverage these demand-side factors, promoting prompt visits to facilities for suspected malaria and challenging patients' misconceptions about the effectiveness of cocktails. Given the importance of the patient-provider interaction and the pivotal role that providers play in ensuring the delivery of appropriate malaria care, future research and interventions should also focus on the supply side factors influencing provider behaviour.