Nanocomposites of acrylonitrile butadiene styrene (ABS) with multi-walled carbon nanotubes (MWCNTs) have been fabricated using a facile solution blending technique with the variable weight of MWCNTs in ABS within a range of 1–5 wt% in the ABS/MWCNTs nanocomposites. Morphological characterization using field emission scanning electron microscope has shown uniform dispersion of MWCNTs in the nanocomposites. Thermal gravimetric analysis has shown improved thermal degradation stability for 5 wt% ABS/MWCNTs nanocomposites in comparison to pure ABS. Thermal expansion analysis of ABS/MWCNTs nanocomposites also showed a significant reduction in thermal strain and coefficient of thermal expansion (CTE) in comparison to pure ABS, with the 5 wt% sample showing a maximum reduction in thermal expansion properties. Mechanical characterization for 5 wt% ABS/MWCNTs nanocomposite, using nanoindentation, showed significant improvement in elastic modulus (90%) and hardness (99%) in comparison to pure ABS. The dynamic mechanical properties of 5 wt% ABS/MWCNTs nanocomposites also showed significant improvement with storage modulus and hardness improving by 153% and 342%, respectively, in comparison to pure ABS. These enhanced thermal and mechanical properties of ABS/MWCNTs nanocomposites enable their applications for a wider scope in various areas of engineering-based application, especially in the automobile industry.