The purpose of this study was to assess the prevalence of right ventricular (RV) systolic dysfunction in adults with anatomic repair of dextro-transposition of great arteries (d-TGAs), and to determine its relation to clinical outcomes across multiple domains (functional status, peak oxygen consumption, N-terminal pro-brain natriuretic peptide, and heart failure hospitalization). Adults with anatomic repair for d-TGA and with echocardiographic images for strain analysis were divided into 2 groups: (1) d-TGA status after an arterial switch operation (d-TGA–ASO group) and (2) d-TGA status after a Rastelli operation (d-TGA–Rastelli group). RV systolic function was assessed using RV global longitudinal strain (RVGLS), and RV systolic dysfunction was defined as RVGLS >-18%. We identified 151 patients (median age 21 years [19 to 28]; d-TGA–ASO group 89 [59%], and d-TGA–Rastelli group 62 [41%]). The mean RVGLS was −22 ± 4%, and 47 patients (31%) had RV systolic dysfunction. The d-TGA–Rastelli group had lower (less negative) RVGLS than that of the d-TGA–ASO group (−19 ± 3% vs −25 ± 3%, p <0.001) and higher prevalence of RV systolic dysfunction (48% vs 19%, p <0.001). RVGLS (absolute value) was associated with peak oxygen consumption (r = 0.58, p <0.001; adjusted R² = 0.28), log–N-terminal pro-brain natriuretic peptide (r = −0.41, p = 0.004; adjusted R² = 0.21), New York Heart Association class III/IV (odds ratio 2.29, 1.56 to 3.19, p = 0.01), and heart failure hospitalization (hazard ratio 0.93, 0.88 to 0.98, p = 0.009). RV systolic dysfunction was common in adults with d-TGA and anatomic repair and was associated with clinical outcomes. Longitudinal studies are required to determine the risk factors for progressive RV systolic dysfunction and to identify strategies for preventing RV systolic dysfunction in this population.