This paper proposes a novel optimization methodology aimed at solving economic dispatch (ED) problem considering valve point effects using invasive weed optimization (IWO) algorithm. IWO was recently proposed as a simple but powerful metaheuristic algorithm for real parameter optimization. IWO draws inspiration from the ecological process of weeds colonization and distribution and is capable of solving general multi-dimensional, linear and nonlinear optimization problems with appreciable efficiency. The proposed method has been applied to three test systems comprising 3, 13 and 40 units. These test systems are also solved using the catfish particle swarm optimisation (Catfish PSO) algorithm - an improved version of PSO - for the comparison and validation of the solutions. The obtained best values have been compared with different methods in literature and the results of them have been discussed. The result obtained proves that the IWO algorithm is efficient and can be used practically for solving economic dispatch problem. A comparative analysis with other settled nature-inspired solution algorithms demonstrates the superior performance of the proposed methodology in terms of both solution accuracy and convergence performances. © School of Engineering, Taylor’s University.