We have developed a fully stretchable triboelectric nanogenerator (S-TENG) using knitted fabrics, offering a promising solution for powering wearable electronics by harvesting human-motion energy. This S-TENG adapts to cloth movement and generates electricity through compression and stretching. Among different fabric structures, rib-knitted fabric showed superior performance, generating up to 23.50 V and 1.05 μA under stretching motions and a constant average power of up to 60 μW under compression at 3.3 Hz. This study demonstrates the feasibility of integrating TENGs into textiles for efficient energy harvesting from human biomechanical movements.