The development of high-performance miniaturized electrochemical energy storage systems is one of the important technological challenges for innovative electronic gadgets. Flexible microelectromechanical systems-based supercapacitors are considered one of the most aggressive on-chip power sources for advanced integrated electronics. Achieving high power efficiency with excellent flexibility and transparency for the micro-supercapacitors is a major challenge nowadays. Generally, these characteristics of micro-supercapacitors are dependent on the fabrication methods, electrical, mechanical and electrochemical properties of the microelectrode materials, current collectors and electrolytes. In the present review, we have summarized the various strategies used in materials engineering to develop flexible micro-supercapacitors and their electrochemical performance characteristics. Meanwhile, this review presents the latest developments in the design, fabrication and application of flexible micro-supercapacitors.