Magnesium boron fibrous composites have been used in the aeronautical/aerospace due to their resistance/weight properties. The focus of the study was to collect detailed behaviour of thermal expansion for controlled rates of heating and thermal cycles through experiments. The results were compared with Schapery model and rule of mixtures for a range of temperatures and fibre orientations. The measured valuesof coefficient of thermal expansion values were in good agreement with the theoretical calculations for the considered 0 and 60 degrees fibre orientations. The behaviour for 90 degrees orientation was dominated by the thermal expansion of magnesium matrix as expected.