Internet of Things helps integrating and connecting the physical devices to the Internet without any human intervention and human to human or human to computer interaction. It represents the future trend and the next biggest revolution unfolding in the IT world. The people and things are connected with anything and anyone, anytime, anyplace, using network or service. It also aims at how IoT can lead to a greener and cleaner environment through Green IoT. This paper gives overview of IoT and Green IoT. It also highlights various technologies and concerns regarding green IoT and how it can reduce energy consumption. This paper enlightens the concept of Internet of Things (IoT), its features, security issues, technology adoption trends.