Introduction The incidence of diabetes has risen dramatically in almost every part of the world in recent decades, with 415 million people living with the disease worldwide. In many Asian countries, the rate of medication non-adherence was reported to be around 40-80%, while in Malaysia non-adherence rate averages 50%. The diabetes patients' adherence to prescription medication is 67.5%, which is lower than that of patients with any other medical conditions. Patients with low medication adherence are more likely to experience clinical complications, repeated hospitalizations, increased mortality, and increased healthcare costs, hence, education on disease and medication adherence is vital now. In Malaysia, there has not been any significant research on the use of online educational materials in improving diabetes medication adherence. Objectives This study was conducted to assess the level of medication adherence among the diabetic population, to analyse the medicine and information-seeking behaviour, and to determine the effectiveness of online educational intervention in improving medication adherence and medicine and information-seeking behaviour among the diabetic population residing in Klang Valley, Malaysia. Methodology Individuals aged 12 years and above with a prior diagnosis of diabetes were identified and randomly distributed (control group n=183, intervention group n =206) from survey form distributed via various platforms online. Data about their medication adherence and information-seeking behaviour were obtained. As part of the intervention, a month of daily general reminders to take their medications and educational materials about diabetes were provided via WhatsApp groups. After a month, the groups were reassessed and the data were compared. Results In this study, an online educational intervention was provided to the intervention group participants using freely available online electronic educational materials on diabetes, and daily reminders to take their medication on time, for one month. The findings showed that most of the respondents in this study had a low level of medication adherence and poor information-seeking behaviour at baseline. However, after being given the online educational intervention for one month, there was a significant improvement in the level of medication adherence and information seeking behaviour among the intervention group. Conclusion Medication adherence is important in risk reduction strategies since the patients’ quality of life can be improved. The resources available online can provide necessary information that supplements a physicians’ counselling. In this study, the participants initially reported having low medication adherence levels and poor medicine and health-seeking behaviour. But when the intervention was introduced, there was a significant increase in the number of people who reported having better medication adherence level and medication information-seeking behaviour. Keywords: Diabetes, education; awareness, hyperglycaemia, medication adherence, information-seeking behaviour.