Abstract The cloud computing is a key computing approach adopted by many organizations in order to share resources. It provides Everything As-A-Service (XaaS). Software-As-A-Service is an important resource on the cloud computing environment. Without installing any software locally, service user can use software as a utility. And enjoy the benefits of SaaS model. Hence SaaS usage is increased drastically, the demand for selecting quality is also increased. This paper presents a novel quality model intended for evaluating software as a service (SaaS), depending on the key features of Software as a service. Because SaaS key features are playing critical role in the quality and differentiating from conventional software quality.