Objective Venous (VTE) and arterial (AT) thrombosis in systemic lupus erythematosus (SLE) are poorly explained and difficult to predict. Leptin and tumour necrosis factor-like weak inducer of apoptosis (TWEAK) have been linked to subclinical atherosclerosis and galectin-3-binding protein (G3BP) to type I interferon activation and a pro-thrombotic environment. Thus, we explore serum G3BP, interferon gamma-induced protein 10 (IP-10), soluble CD163 (sCD163), TWEAK and leptin as predictors of VTE and AT, damage accrual, and all-cause mortality during follow-up in a Swedish SLE cohort. Methods Baseline data were available from 162 SLE patients. VTE (deep vein thrombosis and/or pulmonary embolism), AT (myocardial infarction and/or stroke), damage accrual, and survival data were the main study outcomes and available at follow-up (median of five years). Baseline serum G3BP, IP-10, sCD163, TWEAK and leptin were measured and analysed by univariable and multivariable methods for association to the study outcomes. Results During the follow-up, 10 (6%) VTE and 13 (8%) AT events occurred. The SLICC/ACR Damage Index increased in 78 (48%) patients, and 19 (12%) patients died. In the univariable regression analysis G3BP levels were significantly associated with an increased risk of VTE (hazard ratio (HR) 1.11, 95% confidence interval (CI): 1.01-1.22, p=0.03). This persisted in the adjusted multivariable analyses (HR 1.18, 95% CI: 1.05-1.33, p=0.007). The other biomarkers were not associated with AT/VTE, damage accrual, or all-cause mortality. Conclusion Our study identifies serum G3BP as a novel predictor of VTE in SLE. Further studies are needed to understand the role of G3BP in VTE and translate this into clinical practice.