The prevalence and factors associated with metabolic syndrome (MetS) remain unknown in Malaysian vegetarians. This cross-sectional study aimed to determine the prevalence of MetS among vegetarians in Kuala Lumpur and Selangor and its associated factors. The data on socio-demographic characteristics, vegetarianism practices, lifestyle behaviours, body weight, height, waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose (FBG), and blood lipid profiles were collected from 273 vegetarians. A majority of the respondents were lacto-ovo vegetarians (44.0%), females (64.8%) and Chinese (54.9%). The prevalence of MetS was 24.2%. High BP (48.7%) and high WC (43.6%) were the most common MetS components. Females had lower WC, SBP, DBP, FBG, TG and higher HDL-c (p < 0.05) as compared to males. Multiple logistic regression analysis showed that advancing in age (OR = 1.03, 95% CI: 1.00-1.06), and overweight and obesity (OR = 7.90, 95% CI: 4.13-15.11) were the risk factors of MetS after adjusted for sex. This study found that one in four vegetarians had MetS. The present findings emphasize the need to focus among vegetarians with older age. An intervention program to reduce BMI should be established among vegetarians, especially among those vegetarians who were overweight and obese.