Large-area, flexible, and lightweight textile-based triboelectric generator (TTEG) technologies are promising power supplier by harvesting energy from human motions, wind, and water current. Numerous TTEG systems have been demonstrated. However, the challenges in their applications include the low electric output power, failure under wearing conditions, and adverse effects on the wearable performance like comfort and durability. What is the influence of system integration on the output performance of the TTEGs? What kinds of textile-structures have the most promising performance? How to make an effective TTEG system? In an attempt to answer these important questions, a critical review is presented on the recent advances of wearable TTEG systems in terms of textile structures, selection of materials, working modes, mechanisms of triboelectrification and charge transfer, energy storage, and their integrations. Furthermore, the major approaches or directions for improving the total conversion efficiency and performance of wearable TTEG systems are systematically summarized.