Background: Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that contributes to cardiovascular diseases (CVD), type 2 diabetes mellitus (T2DM), cerebrovascular complications, as well as bone and gastrointestinal disorders, thus regarded as a major global health concern. Abdominal obesity, high blood pressure, high serum glucose, and dyslipidemia are four important components of MetS. These metabolic disorders are modifiable with relevant pharmacotherapy and lifestyle modifications. Patients’ education can be a key element in reducing the poor and inappropriate management of MetS. Objective: The study aimed to assess the knowledge, attitudes, and perceptions (KAP) of MetS among patients with MetS. The study also aimed to determine the cardiovascular risk scores among the patients with MetS, and provide online educational interventions on MetS among these patients. It is also intended to evaluate the effectiveness of pharmacist-led online educational interventions in improving the KAP of patients with MetS. Lastly, to assess the medication adherence behaviors among these patients with MetS. Methods: An online interventional study was conducted among the general population in Klang Valley who have been diagnosed with MetS. The participants were recruited by convenience sampling method. A structured, validated study questionnaire was distributed via social media platforms, as well as study posters embedded with the “Quick Response” code were displayed in prominent areas to recruit eligible participants. Incomplete responses were excluded. The eligible study participants were divided into intervention and control groups, where the intervention group received online educational interventions led by the pharmacist for 15 days. The data was analysed using Statistical Package for Social Sciences (SPSS). Results: A total of 50 participants in the control group and 47 participants in the intervention have completed the survey. Female participants were predominantly involved in both the control (n=32, 64%) and intervention (n=27, 57.4%) groups. Overall, the current study suggests that the majority of the patients with MetS have limited knowledge (n=81, 83.5%), negative attitudes (PRR=40.72%), and positive perceptions (PRR=76.12%) towards MetS. Post-intervention, the KAP towards MetS significantly improved among the participants in the intervention group as compared to the pre-intervention (p<0.01), which was not observed in the control group. The findings also suggested that most of the participants in the current study in both groups have poor to moderate medication adherence (n=71, 73.2%). The online educational interventions elicited a statistically significant change in medication adherence among the patients with MetS in the intervention group (p<0.01). Conclusion: The incorporation of online-based patient education in addition to the therapeutic management of MetS is warranted, which will effectively improve the KAP towards MetS and medication adherence among patients with MetS. Keywords: Metabolic syndrome, hypertension, diabetes, dyslipidemia, obesity, knowledge, attitude, perception.