: Metabolic dysfunction-associated fatty liver disease (MAFLD) is linked to cardiovascular complications, including atrial fibrillation. P-wave indices (PWIs) reflect atrial conduction heterogeneity but have not been fully evaluated in MAFLD. To compare PWIs in MAFLD patients versus controls, assess their association with fibrosis severity, and evaluate their diagnostic performance for MAFLD and fibrosis. : In this retrospective single-center study, 447 subjects were included (noMAFLD: Fatty Liver Index (FLI) < 30 without metabolic dysfunction, n = 205; MAFLD: FLI ≥ 60+ ≥ 1 metabolic risk factor, n = 242). Among MAFLD subjects, the non-alcoholic fatty liver disease (NAFLD) Fibrosis Score (NFS) stratified lower (NFS ≤ -1.455; n = 170), and there was a higher fibrosis risk (NFS > -1.455; n = 72). Standard 12-lead ECGs were digitized for offline PWI measurement. Statistical analyzes included group comparisons, multivariable logistic regression, and ROC curve analysis. : MAFLD patients exhibited a longer PWPT-D2 (63 ± 12 vs. 52 ± 10 ms, = 0.003), PWPT-V1 (68 ± 14 vs. 60 ± 13 ms, = 0.005), PWdis (55 ± 13 vs. 46 ± 11 ms, = 0.010), and PTFV (38 [31-46] vs. 28 [22-34] mm·ms, = 0.021) compared with controls. Within MAFLD, a higher fibrosis risk was associated with a further PWI prolongation (all < 0.015). Multivariate analysis identified PWPT-D2 (OR 1.05 per ms; 95% CI 1.02-1.08; = 0.002) and PWDIS (OR 1.03 per ms; 95% CI 1.00-1.06; = 0.048) as independent MAFLD predictors. ROC curves showed PWPT-D2 had the highest AUC for MAFLD detection (0.78; 95% CI 0.72-0.84) and fibrosis (0.82; 95% CI 0.76-0.88). Combining PWPT-D2 with BMI and waist circumference improved MAFLD discrimination (AUC 0.89; 95% CI 0.85-0.93; < 0.001 vs. PWPT-D2 alone). : PWPT-D2 and PWdis are significantly prolonged in MAFLD and more so with advanced fibrosis. PWPT-D2 may be a simple, noninvasive ECG marker for MAFLD screening and fibrosis staging, particularly when combined with anthropometric measures.