The rapid changes within the economic, social, political and technological environment have a major impact on the labour market, where flexible forms of employment are being used more and more in many industries and in the public sector. Over the years, public sector labour relations tend to converge with private sector labour relations, despite the fact that these two sectors have differences and provide different goods and services, in different ways and with different values. Flexible forms of employment have been applied in the public sector with high frequency and with many types especially in recent years and concern a wide range of jobs. Moreover, the number of the flexible employees in the public sector has increased significantly over the last years, as compared to the number of the non flexible employees. The dynamics and the importance of the flexible forms of employment in the modern public sector need further analysis, taking into consideration the importance of the public sector in the economic and social environment and in the country's development prospects. The subject of the thesis is to examine in detail the application of the flexible forms of employment in the public sector, where important changes are being witnessed in recent decades due to the country's participation in the European Union and the Economic and Monetary Union, as well as due to the economic crisis that the country is still going through. The purpose of the thesis is to highlight and delineate the flexible forms of employment that are applied in the public sector, by presenting the relevant institutional framework and providing data regarding their implementation, identify their growth-promoting factors and analyze the changes they bring, especially as far as the employment status and the labour relations in the public sector are concerned, keeping in mind that they gradually converge with private sector labour relations. On the basis of the above, the main research question guiding the study is how the flexible forms of employment in the public sector affect the convergence of the public and private labour relations. In order to answer this question, it is necessary to review the changes in labour relations and the decline in full-time employment, record the institutional framework regarding the employment of the permanent staff of the public sector, explore the context of the flexible employment in the public sector and the employment status of the flexible employees in the public sector and outline the convergence policies of the public and private labour relations. For this reason, the methodology is based on the systematic and extensive recording, compilation and exploitation of legislation, jurisprudence and administrative acts related to the flexible forms of employment applied in the public sector, highlighting the institutional overturns that have taken place, as well as on data that are available in studies and reports of international and Greek organizations. The analysis of this material, in combination with the analysis of the convergence policies of the public and private labour relations, leads us to the conclusion that the application of flexible forms of employment in the public sector is a vehicle for the deregulation of labour relations, thereby degrading labour relations and converging public and private labour relations. It also appears that flexible forms of employment in the public sector are at the core of other convergence policies of public and private labour relations generally applied. The research aims to enrich the public debate on the evaluation of the application of flexible forms of employment in the public sector, especially regarding labour relations.