This paper provides an overview of the use of small cells (e.g., femtocells) in the Internet of Things (IoT) environments. As a result of rapid increase in the number of mobile connected devices such as smart-phones and tablets, the demand for data traffic is exponentially increasing. In order to satisfy mobile users' requests and meet the requirements of high data traffic, mobile operators have to increase the network capacities dramatically. One of the promising solutions for the network operators to improve coverage and capacity, and provide high data rate services in a less costly manner is the deployment of femtocells related technologies. Femtocells will help mobile operators to provide a basis for the next generation of services which are a combination of voice, video, and data services to mobile users. Moreover, proper traffic modelling and deployment strategies of femtocells will improve the overall performance of the femtocell network. Therefore, in this survey paper, we overview modelling traffic and deployment strategies in femtocells and provide a review for the use of femtocells and their applications in the IoT environments. In addition, we present open research issues associated with IoT-femtocell based applications.