Background: The prevalence of metabolic syndrome (MetSyn) is increasing in Iran. This study was an attempt to determine the effects of a short message service (SMS)-based education intervention on knowledge, attitude, and the adoption of preventive behaviors concerning MetSyn among a sample of employees of Iran University of Medical Sciences (IUMS). Methods: In this randomized controlled trial, conducted from January through April 2021, 144 IUMS staff members  were assigned either to the intervention group (n=72) or to the control group (n=72). Thirty-two text messages were designed, pretested, and sent to the participants’ phones in the intervention group in 32 days. Knowledge, attitude, and the adoption of preventive behaviors vis-à-vis MetSyn were measured in the intervention group before and 1 month after the intervention and compared with those in the control group at the same time points. The data were analyzed using paired t tests and ANCOVA. Results: The mean age of the employees in the intervention and control groups was 42.97±8.80 and 40.81±9.58 years, respectively. The results showed that the mean scores of knowledge (P<0.001), attitude (P<0.001), and the adoption of preventive behaviors regarding MetSyn (P=0.009) were significantly different between the intervention and control groups after the intervention was done via SMS. Conclusions: The results of the present study showed that SMS-based interventions might improve knowledge, attitude, and the adoption of preventive behaviors pertaining to MetSyn among employees.