Turner syndrome (TS) is associated with aortic coarctation, dissection and dilation/aneurysm. Predictors of dissection are not well delineated, making decisions regarding prophylactic root replacement challenging. In other disorders, arterial tortuosity is an imaging biomarker associated with increased risk for aortic dissection and adverse cardiovascular events. We aimed to determine if, in TS, arterial tortuosity was associated with aortic dilation or aortic events. We performed a retrospective cohort analysis of unselected women and children with TS who underwent cardiovascular magnetic resonance angiography (MRA) for a prior prospective study. We calculated tortuosity indices including vertebral artery tortuosity index, aortic arch tortuosity index, thoracic aortic tortuosity index (ATI-D), and aortic tortuosity index to the celiac artery (ATI-C). We compared tortuosity in TS patients against age and gender matched controls. We evaluated univariable and multivariable associations between the tortuosity indices and aortic root and ascending aorta size as defined by z-scores, which give a sense of how far a measurement deviates from the mean. We also studied associations between tortuosity and need for aortic root replacement or aortic dissection. Of 184 subjects, with median age 34 years, mean general aortic root z-score was 0.1 ± 1.2 and mean general ascending aortic z-score was 0.4 ± 1.5. Three patients had aortic dissection, and one had prophylactic root replacement, which all occurred prior to first MRA. Vertebral tortuosity index, ATI-D, and ATI-C all increased with age (p < 0.0001) for all. ATI-C was associated with larger general ascending z-score. In multivariable analysis, ATI-C remained independently associated with larger ascending aortic z-scores. The relationship between aortic indices and surgery/dissection could not be evaluated since all were collected post-surgery/dissection. Thoracic aortic tortuosity as measured by ATI-C is independently associated with larger ascending aortic dimensions. In this population with only three aortic dissections occurring prior to imaging assessment, we could not assess for associations between aortic tortuosity and dissection. Studies including more patients with aortic dissection are needed to draw further conclusions.