The aim of this project is to broaden the knowledge about Service Level Agreements (SLA) within the context of airports and their services offered, focusing on the measurement of quality levels as a key factor to establish this kind of contracts. At the same time, Barcelona Airport is treated aside and a SLA model is proposed, mainly based on building new performance indicators. SLA are a kind of contracts between providers and their customers, which differ from traditional contracts in terms of the new ones being based on performance evaluation as the main basis of the contractual relationship. Overall it is an interesting concept if we apply it to the main actors in aviation and air transport fields, which are airlines, airports and ground handling companies. The last ones become especially relevant if we consider the measurement of the offered service quality. As handling agents operate within the airport facilities, they must offer an excellent customer service which may take the airport to be well considered by their users, them being either passengers or airlines. Currently, from an international point of view, we are really far away from functioning based on performance contracts. Tools such as SLA are still under investigation and development. However, by means of the definition of new performance service indicators, a new model will be proposed, which will provide the tasks taking place at Barcelona Airport with more control and thoroughness. In addition, it is worth saying that no additional economical or environmental costs will be generated.