Topology control is the primary technique of energy saving, and energy saving is also one of the most important objectives in topology control. It consists to keep a minimum number of sensor nodes to operate in active mode with the purpose of conserving energy as well as ensure network connectivity and/or coverage. In this paper, we propose a Geographical Topology Control (GTC) Protocol to reduce energy consumption in wireless sensor networks by sleep scheduling among sensor nodes with the purpose to ensure the network connectivity. GTC divides the network into zones so that a connected backbone can be maintained by keeping a necessary set of working nodes and turning off the redundant ones. Hence, it ensures connectivity and extends the network lifetime by selecting only one active node in each zone. The simulation of the proposed protocol outperforms some existed works in terms of network lifetime, data delivery, scalability, and message overhead. It can consume respectively 80% less energy than an routing protocol which extends the network lifetime.