Linear antenna array design is one of the most important electromagnetic optimization problems of current interest. This article describes the application of a recently developed metaheuristic algorithm, known as the invasive weed optimization (IWO), to optimize the spacing between the elements of the linear array to produce a radiation pattern with minimum side lobe level and null placement control. The results of the IWO algorithm have been shown to meet or beat the results obtained using other state-of-the-art metaheuristics like the genetic algorithm (GA), particle swarm optimization (PSO), memetic algorithms (MA), and tabu search (TS) in a statistically meaningful way.