Machine learning (ML) models are increasingly used in high-stakes decisions, such as insurance pricing and pretrial detention, but often reproduce or amplify biases present in data. To mitigate discrimination, optimal transport (OT) offers a principled way to transform unfair model predictions into fair ones while minimizing performance loss. Moreover, uncertainty-based methods like calibration help assess fairness across sensitive groups, while uncertainty attribution helps identify sources of bias. This research aims to address algorithmic fairness challenges by developing evaluation and mitigation techniques with theoretical guarantees from OT, easily deployable in practice, while integrating fairness into the broader framework of trustworthy AI—enhancing calibration and uncertainty attribution methods to ensure ethical use of ML models by transparency and reliability.