Aim: This study aimed to describe the systolic left ventricular global longitudinal strain (LvGLS) and left ventricular peak early diastolic strain rate (Sre) in adult women with Turner syndrome (TS) and to determine its rela-tionship with exercise capacity and clinical parameters. Methods: In this cross-sectional cohort study, consecutively included adult TS women underwent an electrocardiogram, transthoracic echocardiogram (TTE) and cardiopulmonary exercise test (CPET) on the same day. LvGLS and Sre were measured using 2D speckle tracking analysis (STE) and compared with age-matched healthy female controls. Results: Ninety-four adult women (age 36 ± 13 years) with TS and 32 healthy age-matched female controls were included. Women with TS had a significantly impaired/reduced systolic LvGLS (–17.82 ± 2.98% vs. –21.80 ± 1.85%, p <0.001)and Sre (0.98 ± 0.32 s-1 vs. 1.27 ± 0.19 s-1, p > 0.001), compared to healthy female controls. Furthermore, TS women had reduced diastolic function as measured by conventional echocardiographic parameters: A higher A-wave (p < 0.001), lower E/A-ratio (p = 0.001), longer deceleration time (p = 0.006), and a higher E/E’-ratio (p <0.001).WomenwithTSalsohadasignificantly reduced maximal workload (p = 0.033), reduced oxygen uptake (p < 0.001) and a reduced maximal heart rate (p < 0.001) during exercise. Multivariable linear regression analysis revealed that Age, karyotype and QT-duration were significantly associated with Sre, but not with LvGLS, in the TS population. Conclusion: Systolic and diastolic strain and exercise capacity were significantly reduced in TS women compared to healthy women. No correlation between strain itself and exercise capacity could be demonstrated, but correlations with conventional TTE parameters and baseline characteristics were found.