Overfishing is a global issue that threatens marine ecosystems and economies dependent on fish resources. This thesis analyzes how the EU:s Total Allowable Catches (TAC) system affects the utilization and sustainability of fish stocks. By applying the theory of the tragedy of the commons, the decision-making process regarding TAC and the political factors influencing these decisions are examined. The study reveals that political considerations often lead to TAC levels being set higher than the scientific recommendations issued by ICES, exacerbating the problem of overfishing. The anlysis also identifies where the EU:s TAC system has failed or succeeded in promoting sustainable fishing. The findings indicate that to avoid the tragedy of the commons, more transparent and scientifically grounded decisions are needed, along with effective measures to reduce overcapacity in fishing fleets. This thesis contributes to a deeper understanding of the complexities in fisheries policy and the need for sustainable solutions to preserve marine resources.