In this thesis, an overview of the fibre and matrix options are provided, and the structural performance models for FRPs are considered. Prediction of the structural behaviour of laminates using Classical lamination theory (CLT) is considered in detail. In doing so, the relationship between the applied load and the internal ply stresses and strains is addressed. Moreover, a focus is provided on the prediction of structural microcrack damage and its influence on cross-ply laminate behaviour. Finite Fracture Mechanics (FFM) models offer an accurate prediction of microcracking, but tend to focus on crack initiation and crack density predictions, rather than the effect of damage accumulation on the macro-scale (stress-strain) behaviour. Herein, this shortcoming is addressed - a model of cross-ply microcracking and its impact on the stress-strain behaviour of cross-ply laminates is introduced using a combination of structural CLT and microcracking FFM models. The FFM model calculates the stiffness reductions that inform the CLT model. The requisite mechanical and thermal properties used in the coupled CLT-FFM model are determined experimental, and the structural behaviour of [0m/90n]s and [90n/0m]s cross-ply laminates is described using the new micromechanical model. The combination of CLT and FFM successfully offers a simultaneous micro- and macro-scale prediction of cross-ply laminate behaviour up to catastrophic failure. The model is compared favourably to empirical measurements.