The aim of this master thesis is to investigate whether and how Greek listed companies were influenced by the event of the Greek debt crisis, which emerged in late 2009. The Greek economy has been suffering by endogenous and exogenous problems, which brought the whole country and its economy into a long recession period since 2010. The main sample consist of 269 listed companies, while the selected time frame covers the period from 2005 to 2015. The methodology is based on fourteen indicators that measure the financial and operating performance of a company. Besides the comparison of the final sample, the impact of the crisis is also examined with respect to SMEs and Large companies, as well as to companies from service and manufacturing sector. Findings show that most performance measures exhibit a significant decline in the period post- the beginning of the debt crisis. ^Thus, for the main sample it is documented that profitability, operating efficiency (real sales per employee), liquidity, employment, dividends, output (real sales) and capital investments significantly decrease in the period post-to the beginning of the Greek debt crisis. However, mixed evidence is found concerning the impact of the Greek debt crisis on the capital structure. It is also found concerning operating efficiency that Greek listed companies suffer more by the debt crisis than the economic development of the Greek economy, while with respect to employment Greek listed companies are less affected than overall the Greek economy by the event of the debt crisis. The results for the sub-samples SMEs and large companies are in line with the results of the full sample. Nevertheless, it is found that SMEs are affected more than large companies concerning operating efficiency, employment, output and capital investments. ^Furthermore, it is documented that companies of the manufacturing sector have a higher leverage than companies from the service sector in the period after the beginning of the crisis.