The simultaneous extraordinary electrical and mechanical properties of carbon nanotubes (CNTs) make them ideally suitable for flexible electronics, especially high-performance flexible integrated circuits (ICs), which are the core units of electronic systems for information processing. This paper reviews the recent progresses of high-performance flexible ICs based on CNTs, involving the performance boosting CNT-based thin-film transistors, the implementation of complementary metal–oxide–semiconductor (CMOS) circuits, and the realization of medium-to-large scale integrated circuits and monolithic three-dimension integration. Several examples of system-level applications are also presented, including active-matrix backplanes for flexible display and signal manipulating for sensing. The article ends with a perspective on CNT-based flexible electronics.