This paper presents an experimental and numerical investigation on tension–tension fatigue behavior of hybrid carbon/glass three-dimensional five-directional (3D5D) braided composites. Fatigue tests were carried out under the stress ratio of 0.1. The experimental results show that the fatigue strength significantly decreases as the fatigue life increases and the stiffness gradually decreases as the loading cycles increase. The fatigue life at the stress level within 35 %–50 % ultimate tensile strength (UTS) is within 4 × 103–6 × 105 cycles. The stiffness degradation before failure increases from 39 % to 58 % as the fatigue stress decreases from 50 % UTS to 35 % UTS. Under tension–tension fatigue loading, matrix cracking inside the yarns and interfacial debonding between the yarns and the matrix firstly occur and propagate, then matrix cracking appears in the resin-rich regions and numerous fiber breakage happens until final failure. The fatigue performance and damage mechanisms of braided composites are affected by fiber hybrid mode and braiding methods. Additionally, a mesoscale representative volume element (RVE) model with periodic boundary conditions and a progressive fatigue damage model was developed for the 3D5D hybrid braided composites. The numerical simulation results of fatigue life, stiffness degradation and damage progression have good agreement with experiments, demonstrating the validity of the developed model.