Metabolic syndrome (MetS) represents a cluster of major risk factors known to be associated with the development of aging-related diseases, such as cardiovascular disease and diabetes. Telomere length (TL) is often used as a cellular marker for biological age. Shorter TL indicates increased biological age. It is unknown whether maintenance of a short TL could be predictive for onset of metabolic diseases associated with increasing biological age. A number of studies found significant associations between shorter TL and dysregulated MetS components, but other studies did not confirm this finding. This cohort study investigated the relationship between shorter baseline TL and a worse metabolic profile with less favorable trajectories of MetS components over a 6-year follow-up. Participants included 2842 men and women aged 18 to 65 years who were part of The Netherlands Study of Depression and Anxiety, an ongoing prospective cohort study with 6-year follow-up. Telomere length from leukocytes was determined using quantitative polymerase chain reaction. Metabolic syndrome components (waist circumference, triglycerides, high-density lipoprotein [HDL], cholesterol, fasting glucose, and systolic and diastolic blood pressure) were determined at baseline and after 2 and 6 years. Adjustments were made at baseline and 2- and 6-year follow-up for covariates (sociodemographic, lifestyle, and health factors) that could affect cross-sectional and longitudinal analyses.