Plastic waste is accumulating at an alarming rate, polluting the environment due to various industrial activities. Plastic waste is also non-biodegradable, making global accumulation difficult. Moreover, it is observed that using sustainable building materials encourages the efficient use of wood industry waste. The study thus uses Polyethylene terephthalate (PET) waste combined with wood fibers to make the non-conventional bricks. The two samples considered had 25% and 40% PET waste by weight. All samples were subjected to compressive strength and hardness tests in accordance with the applicable ASTM standards. Since a perfect brick composition should include both the mechanical properties on the higher sides, in the current work, Data Envelopment Analysis (DEA) was utilized to conduct a multi-response analysis and determine the optimal combination of plastic waste and wood fibers for manufacturing non-conventional bricks. The brick containing 25% by weight of plastic waste proved to be the best of the two types of WPCs created in this study, with a grey relational grade value ranging between 2.384 and 3.045.