Load Balancing (LB) is a great challenge in dynamic and heterogeneous environment like Grid. Load Balancing based on the idea of migration of excess load from heavily loaded node to lightly loaded ones. The main goal of LB is to increase resource utilization and decreases response time of jobs. An effective and efficient LB algorithm is required to balance the load in dynamic Grid environments. In this book, a distributed, dynamic hierarchical based model has been proposed to represent the Grid architecture in order to manage load. The main feature of this model is that it supports heterogeneity and scalability and, it is totally independent from any physical Grid architecture. Over the proposed model, different load balancing algorithm has been proposed at each level of hierarchy that is suitable for large scale, dynamic and heterogeneous environments. The proposed algorithm have been used a sender initiated policy for load balancing and it prefers to balance the load within its own level of hierarchy whose goal is to decrease the average execution time of jobs, leading to a high improvement in the global throughput of a Grid.