tIn this paper, an efficient metaheuristic technique is proposed for solving the static transmission expan-sion planning problem. This technique is known as the social spider algorithm. A suitable methodologyfor handling the problem constraints is also proposed. In the proposed methodology, a DC power flowsub-problem is solved for each network resulting from adding a potential solution developed by thesocial spider algorithm to the base network. The proposed algorithm and the accompanying constraintshandling methodology have been tested through solving the transmission expansion planning problemof three benchmark systems having 6-buses, 46 buses, and 87 buses. Excellent performance and newsolutions are demonstrated in the results section. The new solutions achieve a remarkable reduction inthe total investment cost.