Flexible electronics is the research field with interdisciplinary crossing and integration. It shows the promising advantages of novel device configurations, low-cost and low-power consumption due to their flexible and soft characteristics. Atomic layered two-dimensional (2D) materials especially transition metal dichalcogenides, have triggered great interest in ultra-thin 2D flexible electronic devices and optoelectronic devices because of their direct and tunable bandgaps, excellent electrical, optical, mechanical, and thermal properties. This review aims to provide the recent progress in 2D TMDs and their applications in flexible electronics. The fundamental electrical properties and mechanical properties of materials, flexible device configurations, and their performance in transistors, sensors, and photodetectors are thoroughly discussed. At last, some perspectives are given on the open challenges and prospects for 2D TMDs flexible electronic devices and new device opportunities.