Fiber sensors, with their high sensitivity and flexibility, have contributed to the integration of wearable technologies into everyday clothing, enabling both comfortability and efficient data collection. Meanwhile, the rapid advancements in machine learning have substantially boosted the capability of wearable technology to process intricate information collected from the human body and environment. This work offers a comprehensive review of wearable devices that utilize both fiber sensors and machine learning. Various fiber sensors are discussed based on their working principles and dimensions, and an overview of the machine learning algorithms that have been applied with these fiber sensors is presented. Additionally, the advantages, limitations, and concerns of different approaches are highlighted, paving the way for the future development of intelligent wearable devices and systems.