Master's Thesis from the year 2015 in the subject Sport - Sport Economics, Sport Management, grade: 1.3, Birkbeck, University of London (Management), course: MSc Sport Management and Marketing, language: English, abstract: This paper is about whether the number of foreign players might have an influence on the performance of clubs and national teams. Before analysing the mentioned correlation, this research explains in detail all the different potential factors which might also influence performance. This paper highlights different regulations that have a considerable influence on clubs, such as the UEFA home-grown player regulation and different domestic rules. Other sources of impact are the different youth academy systems. The German youth development system has been an important factor in the success of the German national team since its establishment in 2004, which might be due to the increasing number of competitions in which young German players are determined to get a place. The English Premier League is starting to follow in the footsteps of Germany by implementing different regulations to support English players. Italy, however, is showing dramatic differences with regard to its countrywide youth systems because it seems to merely focus on the academies of the different clubs. Similar systems can be found in Spain, which has, nonetheless, two very successful academies La Masia and La Fábrica. Other related factors to consider are language and funding. As English is one of the most spoken languages in the world, the Premier League is attracting players from a variety of countries. Yet as we are living in a modern economic world, the money factor is also quite important. The Premier League is one of the leagues with the biggest revenue streams in the world. The League shares its revenue with the clubs, which they can then spend on players. Hence, the Premier League is the most valued league in football and is spending millions of pounds per year on buying the best players in the world, at the expense of young English players.