Background Medication errors are the most common types of medical errors that occur in health care organisations; however, these errors are largely underreported. Objective This study assessed knowledge on medication error reporting, perceived barriers to reporting medication errors, motivations for reporting medication errors and medication error reporting practices among various health care practitioners working at primary care clinics. Setting This study was conducted in 27 primary care clinics in Malaysia. Methods A self-administered survey was distributed to family medicine specialists, doctors, pharmacists, pharmacist assistants, nurses and assistant medical officers. Main outcome measures Health care practitioners' knowledge, perceived barriers and motivations for reporting medication errors. Results Of all respondents (N = 376), nurses represented 31.9% (n = 120), followed by doctors (n = 87, 23.1%), pharmacists (n = 63, 16.8%), assistant medical officers (n = 53, 14.1%), pharmacist assistants (n = 46, 12.2%) and family medicine specialists (n = 7, 1.9%). Of the survey respondents who had experience reporting medication errors, 56% (n = 62) had submitted medication error reports in the preceding 12 months. Results showed that 41.2% (n = 155) of respondents were classified as having good knowledge on medication error and medication error reporting. The mean score of knowledge was significantly higher among prescribers and pharmacists than nurses, pharmacist assistants and assistant medical officers (p < 0.05). A heavy workload was the key barrier for both nurses and assistant medical officers, while time constraints prevented pharmacists from reporting medication errors. Family medicine specialists were mainly unsure about the reporting process. On the other hand, doctors and pharmacist assistants did not report primarily because they were unaware medication errors had occurred. Both family medicine specialists and pharmacist assistants identified patient harm as a motivation to report an error. Doctors and nurses indicated that they would report if they thought reporting could improve the current practices. Assistant medical officers reported that anonymous reporting would encourage them to submit a report. Pharmacists would report if they have enough time to do so. Conclusion Policy makers should consider using the information on identified barriers and facilitators to reporting medication errors in this study to improve the reporting system to reduce under-reported medication errors in primary care.