In the present work, the effective coefficients of thermal expansion (CTE) of fiber reinforced composites are studied by micromechanical modeling using the finite element method. Representative unit cell models, cylinders which are embedded in cubes with unit dimensions, having different fiber volume fractions were produced using the finite element program ANSYS. Results of various finite element solutions for different types of composites were compared with the results of various analytical methods and with the available experimental results. Also, the expansion behavior of different material systems with respect to fiber content was determined numerically. All of the models and finite element analyses are in good agreement with the experimental data for longitudinal CTEs, however Rosen-Hashin and finite element results for transverse CTE Lire generally in much better agreement with the experimental data than the other methods for all materials investigated. (c) 2005 Published by Elsevier Ltd.