In this cross-sectional study, the authors investigated the associations of objectively measured physical activity (PA) with the prevalence of metabolic syndrome (MetS) in older adults. Accelerometer-derived light-intensity PA, moderate to vigorous PA, and steps per day were measured in (N = 4,652) 70-year-olds in Umeå, Sweden, during May 2012–November 2019. The MetS was assessed according to the American Heart Association/ National Heart, Lung and Blood Institute criteria. The prevalence of MetS was 49.3%. Compared with the reference, the odds ratios for MetS in increasing quartiles of light-intensity PA were 0.91 (0.77–1.09), 0.75 (0.62–0.89), and 0.66 (0.54–0.80). For moderate to vigorous PA, the corresponding odds ratios were 0.79 (0.66–0.94), 0.67 (0.56–0.80), and 0.56 (0.46–0.67). For steps per day, the odds ratios were 0.65 (0.55–0.78), 0.55 (0.46–0.65), and 0.45 (0.36–0.55). In summary, this study shows that greater amounts of PA, regardless of intensity, are associated with lower odds of MetS. With the limitation of being an observational study, these findings may have implications for the prevention of MetS in older adults.