Cloud Computing is without a doubt one of the most significant innovations presented in the global technological map. The number of potential users enrolling and using cloud services increases exponentially on a daily bases. The great demand from online users for cloud services along with the reduced operational costs that the latter offers has motivated many organisations and companies to consider migrating organizational services, data and applications on the Cloud. However, despite the various positive characteristics of all cloud service models like reduced costs, better availability insurance, on demand data storage and computation power, cloud migration may hinder various security and privacy issues that need to be considered before an organization or company decides to move on to the Cloud. This paper aims to reveal the major security and privacy concepts for all three cloud service models and through a systematic analysis to guide the organization’s stakeholders in deciding which service model best fits their needs based on their security and privacy requirements.