Internet of Things (IoT) is an environment in which everywhere and every device became smart in a smart world. Internet of Things is growing vastly, it is implemented using smart devices which involve with Embedded Systems (ESs). Real Time Operating Systems (RTOS) are used in ESs development due to RTOS added important features as RTOS simplifies development and makes systems more reliable. Many researches directed to the Internet of Things, RTOS became a part of IoT development. In this paper, A generic vision and architecture of RTOS for IoT and the way it could be implemented in different applications are presented. Implementation and testing methods of the RTOS for IoT are discussed. Finally, Research directions in using RTOS for IoT are discussed.