Objective The purpose of this study was to examine health professionals’ perceptions of barriers to medication adherence in patients with non-communicable diseases (NCDs) in Fiji. Methods: Interviews were conducted with 25 health professionals (physicians and pharmacists) treating patients with NCDs in Fiji. The interview contained questions regarding barriers to medication adherence for specific NCDs. Results Health professionals’ perception of these barriers were identified and divided into patient-related and non-patient-related factors. The patient-related factors included lifestyle, knowledge, technique, language, and beliefs and culture. The non-patient-related factors were cost and access to medication, therapy-related factors, and support from other people. Conclusion Traditional medical beliefs, medication access and affordability, negative lifestyle habits, and insufficient knowledge about illnesses, medical devices, and medications were identified as barriers to medication adherence in Fiji. Barriers to medication adherence differ according to diagnosis. Knowledge was considered an important factor with respect to adherence to medication regimens, particularly for patients with asymptomatic conditions (e.g., diabetes, hypertension, and stable asthma).