Flexible sensors have garnered a substantial amount of attention recently owing to their potential to revolutionize human lives. The core issue of the growth of high-performance flexible sensors is controlling the attributes of material systems. For the purpose of realizing exotic functions, the use of efficient and extremely practical three-dimensional (3D) systems in device structures is termed as an attractive solution because complex 3D structures are capable of achieving customized behaviors with not only optical but also thermal, mechanical and electrical attributes, which extend their degrees of practicality beyond those that can be attained with conventional, planar material systems. In this review, we first discuss methodologies for the fabrication of 3D multilevel architectures and explain how these programmable materials are capable of enhancing the performance of flexible sensors. Because the electrical, optical and mechanical properties of programmable materials are affected by their structure, shape and size, these factors are of crucial significance in the design and function of flexible sensors. Finally, we offer a discussion on not only recently developed structural materials and their potential applications in flexible sensors but also the key challenges and future directions of this field. (C) 2019 Elsevier Ltd. All rights reserved.