<p>Ensuring the reliability of concrete structures is critical under severe corrosion and complex loading. Thermoplastic glass fiber-reinforced polymer (GFRP), with high corrosion resistance, higher deformation capacity and energy absorption prior to fracture than thermoset-based GFRP, as well as secondary formability, is promising for such applications. However, bending during forming can induce defects that reduce tensile capacity. This study examines the residual tensile strength of bent thermoplastic GFRP rebars through tensile, transverse compression, and bent strength tests with varying radii. A probabilistic model, integrating macroscopic mechanical analysis and the Tsai–Hill criterion, incorporates transverse compression, deformation effects, and uncertainties in material, geometry, and modeling. Parameters were calibrated via Markov Chain Monte Carlo simulation and validated with in-house and literature data (<i>K</i> = 0.99, ± 30% bounds). Sensitivity analysis shows the longitudinal-to-transverse strength ratio (<i>f</i>_u/<i>Y</i>) influences residual strength more than <i>r/d</i>, with <i>r/d</i>≈5–6 recommended. The model provides both mean and distribution-level predictions for reliability-based design of thermoplastic FRP rebars in marine structures.</p>