<p>Ultra-high-performance engineered cementitious composite (UHPECC) is a type of fiber-reinforced composite material characterized by ultra-high tensile strain and strength, high compressive strength, and multiple microcracking characteristics. In this experiment, eleven groups of unreinforced masonry (URM) walls were designed, including two groups of unreinforced control specimens and nine groups of UHPECC and textile-reinforced UHPECC (TR-UHPECC) reinforced specimens. The effects of reinforcement thickness, single- and double-sided reinforcement, textile mesh, and wall height (depth-to-span ratio) on the out-of-plane mechanical behaviors are studied using four-point bending test. The out-of-plane behaviors are compared and analyzed in terms of failure mode, load-deflection response, variable analysis, and ductility factor. The results showed substantial improvements in load-bearing capacity, deformation capacity, and ductility. Shear and flexural failure with ductility characteristics are observed in strengthened URM walls. The double-sided UHPECC reinforced walls exhibited the highest carrying and deformation capacity, increasing by 97.3% and 256.2% compared to the single-side group, respectively. The optimal reinforcement scheme and configuration can be selected in practical applications according to the variable analysis. Finally, based on the experimental results, shear and flexural failure models are proposed to predict the out-of-plane load-bearing capacity of UHPECC and TR-UHPECC reinforced URM walls. The comparison between theoretical and experimental values shows the reliable consistency.</p>