The increasing demand to be connected anywhere, anytime and anyhow has encouraged the deployment of heterogeneous networks having a mix of technologies such as LTE, Wi-Fi, WiMAX, etc. At the same time, most of the new user terminals (e.g. smart phones, tablets, etc.) are equipped with multiple interfaces, which allow them to select the access network that offers the best quality. Managing network in such environment is challenging. Moreover, nowadays quality of experience (QoE) has become a crucial issue due to a phenomenal growth in multimedia traffic. As user satisfaction is the key to success of any service, the network selection should be centered on QoE or the quality perceived by the end user. In other words, a network selection mechanism should select the network that offers the best QoE, while trying to optimize the network resources. In this chapter, we first present a QoE-based network selection mechanism for homogeneous environment. When several points of attachment are available, we propose to use a QoE-based solution that allows users to select the best network while keeping load balanced among them. Then we provide a network selection scheme for heterogeneous environment, which is the main focus of the rest of this chapter. Our proposal takes QoE into account (among other metrics) for network selection and also provides better load balancing between different networks. It is a user-based and network-assisted approach. By providing users with relevant information about the network for decision-making process, this approach is a good compromise for both user and network operator.