Among the recent advances made in the analysis and simulation of the mechanical behaviour of composite materials, calculations on a mesoscopic scale make it possible to take into account the internal architecture of a textile and to compute its deformations. The mesoscopic analysis covers the reinforcement behaviour during manufacturing (draping and permeability) and performance in-service (response to applied loads and strains, including damage development). X-ray tomography (lCT) is a tool well suited for determining the 3D internal geometry of the composite. The current characteristics of the lCT devices allow micrometrescale characterization, providing high-quality geometrical models. The paper presents an overview of lCT-based meso-modelling of textile composites, illustrated by novel modelling results. It covers two segmentation methods (structural tensor and texture analysis), models of the behaviour (deformation response) at meso-scale of textile reinforcements and damage models for textile composites. A set of cases is analysed where X-ray tomography provides the definition of the initial models and the validation of the results obtained by mesoscopic analysis.