Background: The autoimmune illness systemic lupus erythematosus (SLE) may damage numerous organ systems, involving the cardiovascular system. This study aimed to assess the right ventricular systolic function in SLE patients by tissue Doppler echocardiography (TDE). Methods: This prospective single-center study was done on 100 SLE individuals at Banha University Hospital. Patients had a comprehensive medical history, physical examination, laboratory tests, and tissue Doppler imaging echocardiography. Pulmonary arterial hypertension (PAH) was diagnosed regarding tricuspid regurgitation velocity gradient. Various echocardiographic parameters were measured, including right ventricular (RV) end-diastolic diameter, RV anterior wall thickness, peak systolic velocity of tricuspid annulus (S wave), TAPSE, longitudinal strain and strain rate curves and also RV fractional area change (RVFAC). Results: The study revealed a substantial difference in Pulmonary artery systolic pressure (PASP) values among three groups based on PASP (PASP ≤ 30 mmHg for group A; PASP 30-50 mmHg for group B; PASP ≥ 50 mmHg for group C). There were statistically significant differences in various echocardiography measurements, such as TAPSE, RVFAC, RV anterior wall thickness, RV end-diastolic diameter and more between the three groups. Triglyceride levels showed a substantial change among groups, being lowest in group B. Conclusion: TDE is a helpful technique for examining RV systolic function in SLE patients.