Nowadays composites are one of the materials with broad applications. Textile composites are a new type of composites in which a textile preform is the reinforcement phase. The textile preform can be prepared directly in the form of the final composite part. The mechanical properties of a type of textile composites known as weft-knitted composite, including stiffness, strength, and failure mechanism are studied in this research. Considering the different types of knitting techniques of weft-knitted composites, two types of them known as plain weft-knitted and biaxial rib weft-knitted composites are studied. By selecting an accurate 3D geometrical model, a unit cell of the composite is modeled in Abaqus which is a finite element analysis software. Tensile tests are simulated in different directions on the unit cell and the stiffness is calculated. By applying proper failure theories to the model, the strength and critical strain of the composite are predicted and also the critical areas of the unit cell are determined. In the next step, a micromechanical analysis is utilized for estimating the same mechanical properties. This analytical method calculates the stiffness matrix in every single element of the yarns and transforms it to the global coordinates. Finally, the stiffness matrix of the unit cell in global coordinates and also the local stress and strain of all yarn elements are derived. In this method, the failure theories are also applied to predict the strength, critical strain and an estimate of the critical area in the unit cell. In order to obtain experimental results and validate the results of simulations, a number of glass/epoxy biaxial rib weft-knitted composite specimens are manufactured. For this purpose, the preform is prepared using a flat knitting machine and epoxy resin is injected to the glass preform to make a composite sheet. The mechanical properties of the composite are measured through tensile tests and the results are compared with finite element and micromechanical analyses. The predicted stiffness and strength of the two composites have acceptable consistency with the experimental results in some cases and partly acceptable consistency in some other cases. The predicted critical fracture areas are relatively consistent with the experiments and they are introduced as the failure mechanism of the composites. By virtue of the presented finite element model and micromechanical analysis and by knowing the geometrical parameters and the composite’s material, the mechanical behavior of a weft-knitted composite can be predicted prior to its production. Keywords: Biaxial weft-knitted composite, Finite element analysis, Micromechanical analysis, Experimental tests, Stiffness, Strength, Failure Mechanism