<p>Mindfulness is widely recognized for its effectiveness in addressing life challenges, with self-compassion increasingly explored as a potential mechanism underlying its benefits. This study examines whether self-compassion mediates the relationship between mindfulness and self-forgiveness. A three-wave longitudinal study of 164 Polish participants (aged 18–65) assessed mindfulness, self-compassion, and self-forgiveness using validated measures. Structural equation modeling tested the mediation model and alternative pathways, ensuring robust model fit through measurement invariance. Mindfulness predicted self-compassion (β = 0.43, <i>p</i> ≤ 0.001), which in turn predicted self-forgiveness (β = 0.18, <i>p</i> = 0.019), with a significant indirect effect (β = 0.08, <i>p</i> ≤ 0.001). The direct effect of mindfulness on self-forgiveness was not significant (β = − 0.04, <i>p</i> = 0.182). The mediation model demonstrated strong fit (χ²₍₁₅₎ = 23.3, <i>p</i> = 0.078; CFI = 0.977; TLI = 0.971; RMSEA = 0.045; SRMR = 0.038). This study demonstrates that self-compassion mediates the relationship between mindfulness and self-forgiveness, helping to reduce self-criticism and build emotional resilience. The findings support incorporating mindfulness and self-compassion training into interventions for self-forgiveness. Although the sample limits generalizability, the results offer a basis for future research in clinical and diverse cultural settings.</p>