The aim of engineering designs is to obtain results with minimum cost that will provide safety conditions. But the most economical design ensuring security conditions may not be found within the options, even the designer is experienced. Especially in the design of reinforced concrete (RC) structures that consist from two materials with very different mechanical properties and unit costs, it may be more difficult to achieve this purpose. In this study, a methodology based on teaching-learning-based optimization (TLBO) was proposed for optimum design of RC cantilever retaining wall under the static and dynamic loads. During the optimization process, 29 design constraints including retaining wall stabilities (overturning, sliding and soil stress), section capacities (flexure and shear) and RC design rules are checked. In the optimization problem, totally 17 design variables (5 of them related to cross-section dimension and 12 of them related to RC design) are used. In the sizing of retaining wall, the rules of the TS 7994 (Soil Retaining Structures; Properties and Guidelines for Design) are considered. In the RC design, the requirements of the relevant regulations; TS 500 (Requirements for Design and Construction of Reinforced Concrete Structures) and DBYBHY (Specification for Buildings to be Built in Seismic Zones) are considered. The results obtained by the proposed method were compared with the existing methods and the method seems as suitable for the optimum design of the cantilever type RC retaining walls.