Background: Metabolic syndrome (MetS), defined by the presence of three of more metabolic dysregulations such as hyperlipidemia, hyperinsulinemia, central obesity, and hypertension, has been associated with increased risk of cardiovascular disease, diabetes, and various cancers, including invasive breast cancer (IBC). Whether MetS is a risk factor for ductal carcinoma in situ of the breast (DCIS), a non-obligate precursor of IBC, remains unknown. Methods: A total of 198,748 women aged 40–69 years, DCIS- and IBC-free at enrolment in UK Biobank, were included in the present study. Multivariable-adjusted Cox proportional hazards models were used to estimate the association between MetS and DCIS. Results: A total of 1,251 DCIS cases were ascertained during an average follow-up of 11.4 years. There was no association between MetS and the risk of DCIS overall, or by menopausal status. Analysis of individual components of MetS showed an association between central obesity (waist circumference ≥88cm) and increased DCIS risk in postmenopausal women. Conclusions: In this prospective study we found no association between MetS and DCIS risk. Impact: The study findings do not support an association between MetS and this breast cancer precursor.